MFJ MFJ-1270C System Manual Download Page 150

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MFJ-1270C/1274C MANUAL COMMANDS

Page 141

disconnecting, the retry count is immediately set to the maximum number. In
either case, the disconnect message is

*** retry count exceeded

***

DISCONNECTED

Disconnect messages are not displayed when the MFJ TNC is in Transparent
Mode.

DISP

LAY [class]

Mode: All

Parameters:

class

Optional parameter-class identifier, one of the following:

SYNC

displays asynchronous port parameters

HARACTE

displays special characters

displays ID parameters

INK

displays link parameters

ONITOR

displays monitor parameters

IMING

displays timing parameters

EALTH

displays 25 counters*

*The twenty five counters in the MFJ TNC are 16 bits wide, and are ALWAYS
initialized to 0000 on power up or "RESTART".

Summary of Contents for MFJ-1270C

Page 1: ...or television reception which can be determined by turning the equipment off and on the user is encouraged to try to correct the interference by one or more of the following measure Reorient the recei...

Page 3: ...n to copy or for further information should be addressed to MFJ Enterprises Inc P O Box 494 Mississippi State MS 39762 USA The information contained in this document has been carefully checked and is...

Page 4: ...nd NEC 8201 9 IBM PC XT AT 386 486 and compatibles Computer 10 Other Computers with Non standard Serial Ports 12 Terminal Software Requirements 12 Apple Macintosh 13 Apple II II IIe IIc 13 Commodore C...

Page 5: ...34 A Connecting and Disconnecting Exercise 35 Digipeating 37 Unsuccessful Connections 38 Monitoring Channel Activity 39 Your First Packet QSO 40 Starting the QSO 41 Digipeating 42 Monitoring on the A...

Page 6: ...et Up your Easy Mail Mailbox 72 Mailbox Operation 78 Additional Mailbox Features 83 Forwarding 83 Eliciting Reverse Forwards 84 Remote Heard Log 84 Chat Mode 85 Page SYSOP 85 Remote SYSOP 85 Mailbox C...

Page 7: ...8 Watch dog Timer 208 Modem 209 Power Supply 209 RS 232C Handshaking Protocol 210 Jumper Functions 211 HF Tuning Indicator 217 TROUBLESHOOTING 218 General Tests 218 Step 1 Power Supply 218 Step 2 Obvi...

Page 8: ...and Demodulator Frequency Calibration 234 Method I 234 HF Modem 234 VHF Modem 235 METHOD II 235 Set Modulator Tones Using Built in Calibration Software 236 Demodulator Center Frequency Alignment 237...

Page 9: ...MFJ 1270C 1274C MANUAL TABLE OF CONTENTS viii...

Page 10: ...nd to a valid data carrier The new packet collision prevention features Prioritized Acknowledgments and Slottime are installed This new technology helps prevent many packet collisions inherent in the...

Page 11: ...300 1200 and 2400 packet You may also purchased the MFJ 9600 modem board that allows the MFJ TNC to operate at 9600 baud packet Items supplied with MFJ TNC package 1 One MFJ TNC Packet controller 2 O...

Page 12: ...J 5080 Radio connecting cable for Yaesu 8 pin radio MFJ 5084 Radio connecting cable for ICOM 8 pin radio MFJ 5086 Radio connecting cable for Kenwood 8 pin radio MFJ 280 Monitor speaker for transmit re...

Page 13: ...e Commodore C 64 C 128 or the VIC 20 Computer program see Terminal program In order to use the MFJ TNC with your computer the computer must have an RS 232C serial port or a TTL serial port and a progr...

Page 14: ...omputer Interface without MFJ Starter Pack If you are not using a MFJ Starter Packs you should follow the instruction in this chapter for computer interfacing Serial Port Signals The serial port conne...

Page 15: ...cintosh tm Apple II II IIe II gs tm Commodore VIC 20 tm C 64 tm C 128 tm IBM PCjr PC XT PC AT 386 486 most PC compatibles Radio Shack Color Computer tm PC Compatiables Amiga 500 3000 NEC 8201 Table 2...

Page 16: ...purchased from MFJ Enterprises Inc or any MFJ dealer The Starter Pack includes an interface cable for connecting the MFJ TNC to the Macintosh and a terminal program The Starter Pack for Macintosh is M...

Page 17: ...on disk or MFJ 1283 for software on tape If you wish to construct your own cable the information is as follows MFJ TNC J 5 Pin Mnemonic Name C 64 128 VIC 20 Pin 1 RXD Receive Data B C 2 DCD Data Carr...

Page 18: ...r so you may want to obtain a male to female RS 232C extension cable which should be readily available Radio Shack Color Computer The Color Computer series except for the Micro Color Computer uses a 4...

Page 19: ...ed as Data Communications Equipment DCE the technical term for an RS 232C modem Most computers are configured as Data Terminal Equipment DTE If this is the case for your computer you will probably be...

Page 20: ...MFJ 1270C 1274C COMPUTER INTERFACING Page 11 20 Fig 2 3 Serial port wiring with jumpers for auxiliary signals...

Page 21: ...the computer must be tied to the MFJ TNC connector pin 2 The pin on which your computer receives data on must be tied to the MFJ TNC connector pin 3 If your computer requires any other signals you mu...

Page 22: ...s for operation with MFJ TNC Apple II II IIe IIc For the Apple II family of computers with Apple or third party serial interface cards you may use ASCII Express Pro Hayes Smartcom IIe and DataCapture...

Page 23: ...ge Start this program by typing TERM Refer to your PCjr BASIC manual for details on this program For best results with PCjr do not run the MFJ TNC serial port faster than 1200 baud IBM PC and Compatib...

Page 24: ...d NEC 8201 These computers have built in terminal programs in ROM Consult your computer s documentation for instructions in their use MFJ TNC Serial Port Pin Functions This section describes the pins...

Page 25: ...Ready is an output from the MFJ TNC telling the attached device that the MFJ TNC is operational Signal Ground is the common or return path for all signals between the MFJ TNC and the attached device...

Page 26: ...computer to accept data from your TNC If you see nothing switch off your TNC for a few seconds then on again If you still see nothing verify your wiring and restart your terminal program If you see gi...

Page 27: ...on the back of the TNC turn on your MFJ TNC Note that PWR STA and CON LEDs will be lit 5 If the MFJ TNC terminal parameters match your terminal program parameter the MFJ TNC will sign on and the STA...

Page 28: ...ly read the sign on message from the MFJ TNC type DISPLAY followed by a carriage return You should see a lengthy list of items on your screen This verifies the ability of the MFJ TNC to accept and res...

Page 29: ...MFJ TNC to your radio involves connecting the following signals at the TNC Radio Port as shown in Fig 3 1 Pin 1 Microphone audio from the MFJ TNC to your transmitter Pin 2 Ground audio and PTT common...

Page 30: ...btain the specific microphone connector pin designation for your radio from the your radio s manual Appendix A at the end of this Instruction Manual lists pin assignments for some of the most popular...

Page 31: ...the MFJ TNC and install a shorting jumper at JMP L Installing JMP L will eliminating the need of soldering Cx and Rx to the microphone cable Cx and Rx are installed on the MFJ TNC mother board Fig 3 4...

Page 32: ...phone and Speaker For Method 1 shown in Fig 3 5 the MFJ TNC s audio will be fed directly into the microphone connector or similarly connected auxiliary jack and the output of the MFJ TNC will be adjus...

Page 33: ...ally unkey then re key the transmitter by typing the K key If you wish to defeat the watch dog timer install a shorting jumper at JMP4 3 With the MFJ TNC keying the transmitter and transmitting the hi...

Page 34: ...io Input Level The modem in your MFJ TNC is equipped with an advanced phase coherence type data carrier detector DCD with a sensitive tuning indicator These can be used in combination to set the corre...

Page 35: ...microphone A schematic of an external interface box is shown in Fig 3 7 An interface box similar to the one shown in Fig 3 7 is available from MFJ Enterprises Inc or from any MFJ dealers Model No is...

Page 36: ...er After the transmitter has been keyed for a few seconds it will be shut off automatically by the transmit watch dog circuit As you perform the adjustments below you will have to periodically unkey t...

Page 37: ...h your radio in the receive mode open the squelch control so that a steady hiss is heard on a speaker Set the volume control to the minimum volume position The tuning indicator on the MFJ TNC should d...

Page 38: ...t connection is made A small audio amplifier is built in the MFJ TNC to drive the external speaker Volume of the monitor speaker can be adjusted by using the Monitor control on the left side of the MF...

Page 39: ...program 4 Turn on the MFJ TNC The MFJ TNC will sign on with cmd prompt sign J bbRAM LOADED WITH DEFAULTS A MFJ ENTERPRISES INC MODEL MFJ TNC AX 25 Level 2 Version 2 0 Release XXXXX date XX K RAM Check...

Page 40: ...ameter and gives you a new Command Mode prompt Note that commands are entered by inserted a carriage return CR after each command is typed Note also that carriage return may also be marked as enter on...

Page 41: ...e MFJ TNC s default value is 8 bits and no parity If your computer receives 8 bits as data you may have to set space parity since text may otherwise be interpreted as graphics or other special charact...

Page 42: ...CR or CR LF if AUTOLF is ON when 80 characters have been displayed on a line If your computer does not automatically break long lines you will need to set the screen width to the width of your display...

Page 43: ...quite simple Just set the receiver frequency so that the tuning indicator LED is centered in the display Actually there are 2 LEDs which represent the center of the display Either or both may be used...

Page 44: ...nverted to audio signals and transmitted over the radio but they are otherwise just like packets you will be transmitting later on The CONNECTED to message tells you that the connection was successful...

Page 45: ...ls you will have to change the character that returns you to Command Mode See the section on Special Input Characters below Now type a CTRL C The MFJ TNC doesn t echo the CTRL C but you should immedia...

Page 46: ...example situation in which digipeating is useful AD7I N2WX _________ _________ K5FLU You are station K5FLU and you want to have a packet QSO with N2WX There is a mountain in the way and you are not in...

Page 47: ...ive up and display the message retry count exceeded DISCONNECTED The retry count is also used once the QSO has started Each transmission sent to the other station is acknowledged or ACKed by the other...

Page 48: ...ed Type cmd MONITOR ON cmd CONVERS This is a test packet K5FLU CQ This is a test packet Since you aren t connected to another station your packets are sent to the address CQ i e anyone The packet you...

Page 49: ...ISPLAY MONITOR Your First Packet QSO Although there are still a number of features you should be familiar with for comfortable packet operation you are probably eager to get on the air and try out the...

Page 50: ...r transmissions and monitor with his TNC You can also try the following procedure Both you and your friend should set MONITOR ON enter Converse Mode and send some packets Each station should display p...

Page 51: ...CONNE DISCONNECTED Now issue the following command cmd CONNECT K5FLU VIA WB0QRP As before substitute your call for K5FLU and your friend s call for WB0QRP You are requesting a connect to yourself as y...

Page 52: ...exceptions will be noted The character used to return to Command Mode from Converse Mode is by default a CTRL C Sending a BREAK signal also works This character does nothing in Command Mode so if you...

Page 53: ...haracter try setting BKONDEL OFF The MFJ TNC will not try to correct the display but will indicate the rubout with a character BACKSLASH You can restore display correction by setting BKONDEL ON If you...

Page 54: ...unction except at the actual end of the packet You can include any character in a packet including all special characters by prefixing it with the pass character CTRL V For example I wasn t at the mee...

Page 55: ...s In addition the MFJ TNC will ignore the state of the DCD line Although intuition tells you that lower baud rates will reduce the number of packet retries there is usually a small range between too f...

Page 56: ...y from the standard calling frequencies as soon as possible 5 Set FRACK to a sensible long value More detail on HF packet operation is discussed in the next chapter in this instruction manual FAX OPER...

Page 57: ...above but in 3 1 2 disk 3 MFJ 1287 for Apple Macintosh computer 4 MFJ 1282 for Commodore C 64 and C 128 in 5 1 4 disk If you are using one of the above terminal programs which supports 2 level FAX op...

Page 58: ...obtained from Popular Communication Magazine FREQUENCIES KHz USB LOCATIONS 4 271 00 9 890 00 13 510 00 Halifax Canada 8 502 00 12 750 00 Boston MA 9 389 50 11 035 00 Brentwood NY 4 793 50 10 185 00 12...

Page 59: ...g flow control and other control functions You can change any of these special characters to customize the MFJ TNC to suit your applications your computer or your whim Most of the characters are set b...

Page 60: ...computer manuals A table of ASCII codes for control characters follows Dec Hex Control Mnemonic Dec Hex Control Mnemonic 0 00 CTRL NUL 16 10 CTRL P DLE 1 01 CTRL A SOH 17 11 CTRL Q DC1 2 02 CTRL B STX...

Page 61: ...ed off the screen The MFJ TNC will be in Command Mode after a reset or power up After a power off power on sequence all operating parameters of the MFJ TNC are re initialized to the parameter stored i...

Page 62: ...e several ways to enter a data transfer mode from Command Mode You can type the command CONVERS or K to enter Converse Mode or the command TRANS or T to enter Transparent Mode and the MFJ TNC will imm...

Page 63: ...aracter your input will be packetized and transmitted anyway The default send packet character is CR but you can specify any character with the command SENDPAC You may also choose to have the send pac...

Page 64: ...Mode entry DELETE character deletion MFILTER characters to be filtered in monitored packets PASS insert following special character REDISPLA re display current line SENDPAC send current packet START S...

Page 65: ...ified in Transparent Mode Data is sent to the computer exactly as it is received over the radio including all 8 bits of each byte received Features such as auto linefeed insertion and screen wrap are...

Page 66: ...command In Converse Mode the buffer may fill up for any of several reasons you may be using a faster serial port baud rate than the radio data rate radio data transmission may have slowed down becaus...

Page 67: ...are set to CTRL S and CTRL Q by default but they may be changed The commands XON and XOFF set the characters which will be sent to the terminal by the MFJ TNC and the commands START and STOP set the...

Page 68: ...details on the interface required for hardware flow control Type in Flow Control Type in flow control enabled with the command FLOW is really a display feature It can keep the MFJ TNC from interrupti...

Page 69: ...ry station ID or SSID This is a number from 0 to 15 appended to the call sign with a dash cmd MYCALL W3IWI 3 If you don t specify the SSID extension it will be 0 and the MFJ TNC won t explicitly show...

Page 70: ...special message sent automatically to stations connecting to you you can specify the message with the command CTEXT This message can consist of any text string up to 120 characters and you may include...

Page 71: ...he night limited only by the amount of available RAM The MFJ TNC can operate unattended for extended periods of time If you would like to have the MFJ TNC operate as a digipeater but not connect with...

Page 72: ...g Version 2 0 In addition the command CHECK controls a timing function that depends on the protocol version selected You can specify the address to be used for unconnected packets as well as intermedi...

Page 73: ...eater keyup delay than is required for direct communications Furthermore the extra keyup delay is not required if the repeater has not had time to drop since the last transmission The command AXDELAY...

Page 74: ...n 1 in seconds where n is the number of digipeaters in use for this connection Acknowledgments of digipeated packets are made from end to end and digipeaters do not acknowledge the packets they relay...

Page 75: ...MAXFRAME This does not mean that t e MFJ TNC will wait until several packets have been entered before transmitting MAXFRAME in combination with the command PACLEN which sets the maximum number of char...

Page 76: ...p a connection time out with the command CHECK which specifies a time in multiples of 10 second intervals This function prevents the MFJ TNC from getting stuck in a connection when the other station d...

Page 77: ...omeone set MCON OFF If you want to monitor stations selectively you can set up a list of up to eight callsigns with the command LCALLS The callsigns in this list are regarded as buddies i e the only s...

Page 78: ...V7B N2WX D indicate connect and disconnect packets Disconnect acknowledgments are designated UA and DM packets are DM You can cause the MFJ TNC to filter certain characters from monitored packets with...

Page 79: ...en set To enable this function set MSTAMP ON You can also time stamp connect and disconnect messages with the command CONSTAMP ON Multi Connect Guide Multiple connection capability is a very powerful...

Page 80: ...ween 0 and FF This may allow you to use 8 bit characters AWLEN 8 if your terminal or computer is capable of generating such characters This could help prevent confusion in interpreting incoming data f...

Page 81: ...es addressed to him The Easy Mail mailbox in the MFJ TNC provides approximately 8K bytes of memory for message storage However you can increase the mailbox memory on your MFJ TNC to 32K 128K or even a...

Page 82: ...me your MFJ TNC is powered up 4 Type MAILBOX ON CR Now your MFJ TNC is ready for simultaneous Mailbox Packet operations You as the SYSOP can access your Mailbox by typing SYSOP CR Your MFJ TNC will re...

Page 83: ...MYMcall The callsign of the BBS you wish to Forward the message to is placed here This BBS should be the one where the person whom you are sending the message to gets his mail From The callsign of th...

Page 84: ...t from MYMcall P Messages with this flag set are private to the sender recipient and the SYSOP Only the person to which the message is addressed to can read or kill it The local or remote SYSOP can re...

Page 85: ...be listed They all will have the slot number flag field the destination callsign originator callsign subject field Also the Mailbox command line will be on the next line M This allows the remote user...

Page 86: ...to read the message in slot nn Where nn is a particular slot number This command works the same as the R command except its for reading the individual slots S call This allows the remote user local o...

Page 87: ...es the explanation of the commands which are on the Mailbox command line Now lets get into a little of the Mailbox operation If you have any questions about the Mailbox commands we believe they will b...

Page 88: ...d with Title _ The user will enter the message subject title at cursor prompt then press the RETURN key The Mailbox will respond with Send msg Control Z or EX to end _ The user will then enter the mes...

Page 89: ...t a All messages must have been read and the message flag must be a Y b The callsign contained in the MYMcall must be the same as the callsign in the MYcall command If the above conditions are met the...

Page 90: ...imum slots per memory bank is 99 After the Mailbox lists all messages it will issue the Mailbox prompt nn free n Mailbox B E H elp J K L M R S T 6 Anyone who accesses the Mailbox can read messages or...

Page 91: ...end of the message the Mailbox prompt will be issued 7 The remote user can also disconnect from the Mailbox without having to issue a CTRL C D and a RETURN All that needs to be done is to type B to lo...

Page 92: ...his manual In order to conserve RAM space the SYSOP may specify that forwarded messages be killed upon successful forwarding However if conserving RAM is not a concern then forwarded messages will be...

Page 93: ...off of the mailbox prior to their being forwarded to the legitimate destination When all messages are forwarded if the destination mailbox supports reverse forwarding as determined by in it s SID then...

Page 94: ...ut is used when a connect is made to the MYMcall callsign It is limited to 120 characters in length If MCText is empty then no message will be sent Idle Timeout The Mailbox incorporates an idle timeou...

Page 95: ...STA MAIL LED will not flash Mailbox Messages You have mail Upon access to a mailbox this message will appear if there are messages addressed to you EH This message occurs when a command issued is not...

Page 96: ...ANCED OPERATION Page 87 None found A parameterless Kill or Read command did not find any messages addressed to the user No mail A parameterless read command did not find any mail addressed to user or...

Page 97: ...roblems that occur when there are two or more stations waiting to transmit when a third is already transmitting Before slotting the first two stations are definitely going to transmit at the same time...

Page 98: ...his obviously wastes a lot of time which could be better used clearing the channel of some of the legitimate offered load It is this feature of the current AX 25 protocol that accounts for most of the...

Page 99: ...om being sent beyond the FRACK timer limitation In fact the FRACK timer becomes relatively meaningless in this context However in the current firmware release The FRACK timer is still active and must...

Page 100: ...equired for the local station s squelch if used and TNC DCD circuits to allow generation of a DCD true signal in the local TNC Ideally once the proper value for this timer is ascertained all stations...

Page 101: ...e on the slot time dice SLOTS represents an n 1 sided dice the MFJ TNC throws before transmitting The SLOTS command allows any number of slots from 1 thru 127 to be defined SLOTS n REMARKS 1 Disables...

Page 102: ...quires to transport carrier information from one station to another on the channel Other Related Parameters Several of the existing TNC parameters will affect the operation of the modified protocol Mo...

Page 103: ...in the context of the new protocol However in this release both timers are still active and should be set to 0 when using the new protocol Initial Parameter Settings Summary The settings for use at 12...

Page 104: ...set their DWait value to one that is compatible with the new system users A reasonable DWait setting for 1200 baud use would be 73 For 300 baud work it would be 76 While these settings seem extremely...

Page 105: ...it can possibly do if CSMA is working right is reliably pass about 620 characters per unit time If it is offered more than this to handle performance falls off sharply with increased offered load Curr...

Page 106: ...y using the escape to cmd mode sequence for TRANSPARENT connections Use CTRL C three times default or asynchronous BREAK Packet Picture transfer to the computer screen Packet pictures can also be rece...

Page 107: ...ependently by using the audio output level adjustments R157 on the left side of the MFJ TNC with a small screw driver The modem center frequency used by the MFJ TNC for all of the narrow shift AFSK mo...

Page 108: ...be necessary to use a tone pair centered on the radio s filter rather than the standard 2125 2295 or 1600 1800 Hz pair If the radio lacks IF shift capability this will almost certainly be necessary If...

Page 109: ...band rather than upper sideband if you are going to use a CW filter in the radio for packet operations The reason for this is simple The filter designed for CW operation is usually centered approximat...

Page 110: ...ut less than 50 percent 8 Carefully adjust the IF shift control on the radio to produce maximum DCD activity This is the optimum point for the filter center frequency Note the position of the IF shift...

Page 111: ...ed to ignore background noise while still being able to promptly respond to a valid data carrier It has a hang time feature that prevents DCD dropouts when short multipath hits occur or collisions put...

Page 112: ...s already helped you avoid the DCD and tuning indicator difficulties Configuring your radio bandwidth to match the spectral characteristics of the HF packet FSK signal will allow you to avoid the mode...

Page 113: ...dicate you should tune higher while the other side of center means to tune lower Once you have the other station tuned in you may initiate a connect request just as you would on VHF Many BBS stations...

Page 114: ...a station which has no tuning indicator can eventually get you tuned in using this type of signal as he can tune around and watch his screen to see where printing is effective If you are meeting a fr...

Page 115: ...cedure for a scheduled contact Please use care in selecting the QSO frequency so as to avoid unnecessary interference to other amateur services As in all amateur communication modes it is polite to li...

Page 116: ...figure your station so that you can hear the activity on the channel This will allow you to easily avoid interfering with other stations and also to quickly diagnose the problem when throughput sudden...

Page 117: ...ts to connect to you just to be ignored 7 If your radio allows you to select the AGC time constant fast or slow AGC set it to the fastest setting available to you If you cannot select fast AGC it may...

Page 118: ...operating parameters have been selected set KISS ON and then issue a RESTART command The CON and STA LEDs will blink on and off three times to indicate that the MFJ TNC has entered the KISS mode Now y...

Page 119: ...o adapt the MFJ TNC to his environment Entering Commands You may use either upper case capital letters or lower case small letters when you enter commands In order to have the MFJ TNC accept a command...

Page 120: ...command entry contains several sections as follows COMMAND NAME The boldface command name at the top of the entry is the word you will type in order to have the MFJ TNC execute this command The comma...

Page 121: ...powers of 16 analogous to the powers of 10 represented by a decimal number The numbers 10 through 15 are denoted by the hex digits A through F For example 1B 1 16 11 27 120 1 16 16 2 16 0 288 A parame...

Page 122: ...may optionally include the keyword VIA followed by a list of one to eight callsigns call2 through call9 The callsigns in the list if included must be separated by commas as shown or by blank spaces A...

Page 123: ...AWLEN 8 This may be desirable for example if you are using a special non ASCII character set Bit 7 is always removed in Command Mode since commands require only the standard 7 bit ASCII character set...

Page 124: ...s It should reflect the time it takes for an acknowledging TNC on the channel to keyup send it s acknowledgement and release the PTT This represents the time required to send a response frame with no...

Page 125: ...N OFF Mode Packet Default ON Parameters ON A linefeed character LF is sent to the terminal after each carriage return character CR OFF A LF is not sent to the terminal after each CR AUTOLF controls th...

Page 126: ...AWLEN 8 Alternatively you can use Converse Mode and set AWLEN 8 and 8BITCONV ON however the data you then send must handle the Converse Mode special characters with the PASS prefix If the AWLEN comma...

Page 127: ...delay transmission for some time after the RF carrier is present require some amount of time to get RF on the air If you are using a repeater that hasn t been used for packet operations before you wi...

Page 128: ...t n in 120 ms intervals The value you set on MFJ TNC for AXHANG will thus be 6 5 the value used by a TNC 1 user for the same hang time when converting round down to the nearest integer BBSMSGS ON OFF...

Page 129: ...ists of the text specified by BTEXT in a packet addressed to BEACON and sent via the digipeat addresses specified by the UNPROTO command if any If the keyword EVERY is specified a beacon packet is sen...

Page 130: ...ve a paper output display or if your terminal does not respond to the BACKSPACE character CTRL H you should set BKONDEL OFF The MFJ TNC will type a BACKSLASH for each character you delete You can disp...

Page 131: ...this parm tells the TNC what the DLC address is of the host ex MTHOST Default is 254 BTEXT text Mode Packet Default Parameters text Any combination of characters numbersand paces up to a maximum leng...

Page 132: ...d LCALLS which sets up a callsign list These commands determine which packets will be displayed when you have set MONITOR ON BUDLIST specifies whether the callsigns in the list are the ones you want t...

Page 133: ...ates the modulator and Toggles the PTT line on off Q Quits the calibration routine and returns to command mode CALSET n Mode All Default None Parameters n 0 65535 Specifying the count setting for use...

Page 134: ...ou can not cancel an input line using the cancel line character Note that if your send packet character is not CR the cancel line character will cancel only the last line of a multi line packet To can...

Page 135: ...You can use the cancel display feature if you inadvertently do something that causes the MFJ TNC to generate large amounts of output to the terminal such as giving the DISPLAY command or setting TRAC...

Page 136: ...s This might happen if propagation changes unexpectedly or an intermediate digipeater station is turned off In order to prevent this sort of lockup the MFJ TNC will try to clean up the link if the spe...

Page 137: ...to get an acknowledgment RESTART and power off on cycling will not affect this connected state This command only takes effect when a connection is established It functions on a stream by stream basis...

Page 138: ...last first second third TNC terminal command command command now in input mode mode mode Command entry entry entry Mode character character character longer shorter shorter n than n than n than n CMSG...

Page 139: ...OTE Use this command with care If you find you re able to receive connects yet never get data it s possible CMSGDisc has been left on It s also possible is that RS 232 DCD is holding the terminal off...

Page 140: ...in after a connection is established The connection may result either from a connect request received over the air or a connect initiated by a CONNECT command that you issued For most operations you w...

Page 141: ...rough digipeaters If NEWMODE is ON the MFJ TNC will immediately enter Converse Mode or Transparent Mode as specified by the command CONMODE If NEWMODE is OFF the MFJ TNC will enter Converse Mode or Tr...

Page 142: ...ion trying to connect will replace call All connect requests from stations with totally blank callsigns are rejected with a busy response The MFJ TNC will also issue a DM packet or busy signal to the...

Page 143: ...to exit from Command Mode into Converse Mode Any link connections are not affected Once in Converse Mode everything you type is packetized and transmitted over the radio Typing the Command Mode entry...

Page 144: ...mode since it eliminates the delays while long packets are being typed CR ON OFF Mode Packet Default ON Parameters ON The send packet character normally CR is appended to all packets sent in Converse...

Page 145: ...ght now but you may leave a message To clear the CTEXT text without issuing a RESET command use a or as the first character in the message You cannot connect to yourself and see your CTEXT unless goin...

Page 146: ...oes not check thoroughly for the correct number of days in a month so you should use some judgment when you set the date The date time parameter is used by the commands CONSTAMP and MSTAMP to time sta...

Page 147: ...format for entering the time using DAYTIME is not affected For example if DAYUSA is ON then July 2 1984 at 9 28 44 AM would be displayed as cmd DAYTIME 07 02 84 9 28 44 If DAYUSA is OFF the same date...

Page 148: ...his should work fine with virtually any HF radio stable enough to consider using on HF packet DELETE ON OFF Mode Packet Default OFF Parameters ON The delete character input editing character is DELETE...

Page 149: ...rations and does not interfere with normal operation of a packet station In the spirit of cooperation typical of Amateur operation you will probably want to set DIGIPEAT ON most of the time However yo...

Page 150: ...ent Mode DISPLAY class Mode All Parameters class Optional parameter class identifier one of the following ASYNC displays asynchronous port parameters CHARACTE displays special characters ID displays I...

Page 151: ...SENTRNR ASYRXOVR Increases when the software does not service the asynchronous receiver in time Indicates data from the user to the MFJ TNC is being dropped This error counter should never become non...

Page 152: ...RS Increments each time a received frame is thrown out due to it being too short suffering overrun s or it having a bad CRC Latter occurs only when CRC checking is enabled i e HGARBAGE is OFF This cou...

Page 153: ...described and the setting of HEALLED are displayed in response to the health inquiry DISPLAY is an immediate command and with no class parameter will cause all control parameters and their current val...

Page 154: ...en the command ACKPRIORITY is ON ECHO ON OFF Mode All Default ON Parameters ON Characters received from the computer or terminal are echoed by the MFJ TNC OFF Characters are not echoed This command co...

Page 155: ...IRMRNR should be always be set ON when conversing with network nodes for example NET ROM In other cases it is recommended that FIRMRNR be left OFF unless you can be assured the other TNC you are conne...

Page 156: ...ad 2 Must have a callsign in the addresses that are different from MYMCALL After forwarding each message flag is set to F to prevent further forwards When all messages are forwarded if the dest bbs su...

Page 157: ...FJ TNC makes use of the Data Carrier Detect signal from the modem to avoid collisions and acknowledges multiple packets in a single transmission with a single acknowledgment When full duplex mode is e...

Page 158: ...ine N2WX KV7D Sorry I m not quite ready yet If you have set MRPT ON or enabled MSTAMP you may wish to set HEADERLN ON as the packet header quickly becomes long enough to fill a screen when these funct...

Page 159: ...ion consists of an unsequenced I frame whose data field is your station identification The identification packet is addressed to the CQ address set by the UNPROTO command Your station identification i...

Page 160: ...as TCP IP and other programs which use the Serial Link Interface Protocol SLIP Before enabling KISS make sure radio baud rate and terminal baud rate are set to the desired values The terminal s baud...

Page 161: ...ones you want to ignore or alternatively are the only ones you want to listen to If you want to listen only for packets from a limited list you should enter your selected list with LCALLS and set BUD...

Page 162: ...n Transparent Mode Input characters and echoes are not case translated If your computer or terminal does not accept lower case characters it may react badly if the MFJ TNC sends such characters to it...

Page 163: ...turned on line feeds are totally ignored except in transparent mode MAILBOX ON OFF Mode Packet Default ON When the MAILBOX command is set to ON all of the mailbox functions are active Note that the M...

Page 164: ...under the same format as the MYCALL CONNECT and other callsign commands SP call Lets you Send a personal message to the specified callsign This is a private message which can only be read by the orig...

Page 165: ...LED is OFF MALL ON OFF Mode Packet Default ON Parameters ON Monitored packets include both connected packets and unconnected packets OFF Monitored packets include only unconnected packets This command...

Page 166: ...nk is good there is an optimum relationship between the parameters set by these commands so that the maximum number of characters outstanding does not exceed the packet receive buffer space of the MFJ...

Page 167: ...another station you should set MCON OFF MCTEXT Mode Mailbox Default Text Any combination of characters and spaces up to 120 characters in length This command works like CTEXT except that MCTEXT is sen...

Page 168: ...u can use this command in conjunction with MHEARD to keep track of the stations on the air over a given period of time such as an evening or a week Clear the list of stations heard when you first begi...

Page 169: ...TNCs on the RS232 port are enabled MODE Mode All MODE is a immediate command The MODE command selects which mode the MFJ TNC will be operating in The MODE command is followed by two characters which d...

Page 170: ...ot monitor MNONPRIN has no effect on data received during connections MONITOR ON OFF Mode Packet Default ON Parameters ON Monitoring of all packet activity is enabled OFF Monitoring of all packet acti...

Page 171: ...urce and destination stations for monitored packets This command affects the way monitored packets are displayed If MRPT is OFF only the originating station and the destination are displayed for monit...

Page 172: ...ength of the address display and you may wish to set HEADERLN ON as well to display this information on a separate line MTIMEOUT n Mode Packet Default 30 Parameters n 0 250 Specifying 10 sec intervals...

Page 173: ...n including SSID on the air at once The SSID can be used to distinguish two stations with the same Amateur call The SSID will be 0 unless explicitly set to another value MYALIAS call n Mode Packet Def...

Page 174: ...ser Sebastian Z 32958 and the tagline would look like this R 920801 1200 N5AUV MLBFL FL USA NA N2WX User Sebastian Z 32958 8 MYMCALL callsign Mode Mailbox Default blank This is the dedicated callsign...

Page 175: ...TNC will return to Command Mode Bulletin board systems compatibility with TNC 1 If you have a Bulletin Board program designed to work with TNC 1 you should set NEWMODE OFF if the program relies on th...

Page 176: ...ith the receiving bbs KB4VOL NOMODE ON OFF Mode Packet Default OFF Parameters ON The MFJ TNC will only switch modes command converse or transparent upon explicit command OFF The MFJ TNC will switch mo...

Page 177: ...eed to set NUCR ON if your terminal misses one or more characters after responding to a CR If this is the case you will sometimes see overtyped lines NULF ON OFF Mode Packet Default OFF Parameters ON...

Page 178: ...mand Modes PACLEN n Mode Packet Default 128 Parameters n 0 255 Specifying the maximum length of the data portion of a packet The value 0 is equivalent to 256 The MFJ TNC will automatically transmit a...

Page 179: ...al stops for n 100 ms In no case will a zero length packet be produced and the timer is not started until the first byte is entered A value of 0 for n is allowed and causes packets to be gene rated wi...

Page 180: ...even though that character may have some special function For example suppose you have set COMMAND 3 specifying that CTRL C is your Command Mode entry character If you use a Bulletin Board program th...

Page 181: ...ight be enabled for testing a marginal RF link or during operation under other unusual circumstances If you set PASSALL ON and monitor a moderately noisy channel you will periodically see packets disp...

Page 182: ...kill mes sages to or from himself plus any messages of type T raffic This parameter may be reset to the blank no remote sysop state by entering a or blanking code RESTART Mode All RESTART is an immed...

Page 183: ...ed with BACKSLASH characters rather than by trying to correct the input line display The redisplayed line will show the corrected text You can also use this character if you are typing a message in Co...

Page 184: ...command FRACK A value of 0 for n specifies an infinite number of retries If the number of retries is exceeded the MFJ TNC goes to the disconnected state with an informative message if not in Transpar...

Page 185: ...the beginning of a received data unit header When RXBLOCK is ON data from other stations will be sent from the MFJ TNC in the following format FF L0 L1 PID DATA prefix length pid data The fields abov...

Page 186: ...to be tuned Make sure JMP8 JMP7 and JMP4 are installed 3 Compute n 9600 Bit Rate Where the bit rate is the same as the baud rate in packet modes and the baud rate in all other modes See CALSET Adjustm...

Page 187: ..._____________________ R113 HP R106 HP L R77 VP H CALSET 32 2125 247 2200 240 R79 VP R78 VP L R119 VB H CALSET 8 1200 438 2975 177 NOTE Separate procedure required to do alignment of CW demodulator cen...

Page 188: ...rameters n 0 255 Specifying the screen or platen width in characters of the terminal This value is used to properly format terminal output A CR LF sequence is sent to the terminal at the end of a line...

Page 189: ...thru 127 to be defined SLOTS n REMARKS 1 Disables Slotting 2 4 This should be the default setting 8 Use only if the channel is VERY busy 16 VERY VERY VERY busy 32 You get the idea 64 128 Might as wel...

Page 190: ...MFJ TNC will only respond to hardware flow control CTS If the same character is used for both the User Restart and User Stop characters the MFJ TNC will alternately start and stop transmission upon r...

Page 191: ...am identifier This is particularly useful when operating with multiple connections allowed It is somewhat analogous to the use of MRPT to show digipeat paths when monitoring In the example below the c...

Page 192: ...OFF Parameters ON Double all received STREAMSWitch characters OFF Do not double received STREAMSWitch characters This command is used to display received STREAMSWitch characters by doubling them The...

Page 193: ...cter see the STREAMDBL and STREAMCA commands SYSOP Mode Packet Mailbox Immediate command When the MAILBOX is ON the System Operator can access the mailbox by typing the immediate command SYSOP All com...

Page 194: ...ault OFF Parameters ON Trace mode is enabled OFF Trace mode is disabled This command is used to enable the protocol debugging function When TRACE is ON all received frames will be displayed in their e...

Page 195: ...ed correctly in the ASCII column Non printing characters and control characters are displayed in both ASCII fields as You can examine the hex display field to see the contents of the sub station ID by...

Page 196: ...ol is available to the MFJ TNC to control output from the terminal TRIES n Mode Packet Default NONE Parameters n 0 15 Specifying the current RETRY level on the currently selected input stream This com...

Page 197: ...if it appears that the station you re working is unable to successfully receive your packets despite your adequate signal This failure of some TNCs to receive TXDIDDLEd packets may be a result of some...

Page 198: ...e PTT and when it starts sending packets is specified in terms of how long it takes to send TXDELAYC characters at the current radio baud rate TXDELAYC controls a new timer that runs after the regular...

Page 199: ...in Transparent Mode If TXFLOW is OFF the MFJ TNC will use only hardware flow control and all data sent to the terminal remains fully trans parent If TXFLOW and XFLOW are ON the MFJ TNC will use the M...

Page 200: ...nects and unacknowledged packets remain UNPROTO call1 Mode Packet Default CQ VIA call2 call3 call9 Parameters call1 Callsign to be placed in the TO address field call2 Optional digipeater call list up...

Page 201: ...incoming connections onany free stream USERS 1 allows incoming connections on stream A only USERS 2 allows incoming connections on streams A B USERS 3 allows incoming connections on streams A B C and...

Page 202: ...cket activity This command can also be used for testing using loopback or direct wire connections when PTT operation is not relevant XOFF n Mode All Default 13 CTRL S Parameters n 0 to 7F Specifying a...

Page 203: ...the MFJ TNC to the computer or terminal to restart input from that device You can enter the code in either hex or decimal This character would ordinarily be set to CTRL Q for computer data transfers I...

Page 204: ...inst the correct checksum given for the firmware version you are using bbRAM loaded with defaults This message appears along with the sign on message above if the battery backed up RAM checksum verifi...

Page 205: ...hen returned to Command Mode You will be allowed to enter one of these modes when some of the packets have been successfully transmitted Mailbox Messages Expected bank n x This message occurs when you...

Page 206: ...ssage Space STANDARD 30 2 900 Bytes 32K 99 32 000 Bytes 128K 99 Bank 128 000 Bytes 512K 99 Bank 512 000 Bytes Denotes no memory expansion Denotes memory expansion of the size specified by the numeric...

Page 207: ...etters including at least one letter Punctuation and spaces are not allowed The sub station ID if given must be a decimal number from 0 to 15 separated from the call by a hyphen EH This message occurs...

Page 208: ...long a command line and the line was ignored This might happen for example if you try to enter too long a message with BTEXT or CTEXT If you get this message the previous text entry was not changed to...

Page 209: ...me sequence you would enter to initiate the connection Link state is DISCONNECTED No connection currently exists You may issue the CONNECT command to initiate a connection Link state is CONNECT in pro...

Page 210: ...f a CONNECT command you issued or of a connect request packet received from another station connect request call1 VIA call2 call3 call9 This message indicates that the MFJ TNC has received a connect r...

Page 211: ...t to re synchronize frame numbers with the MFJ TNC on the other end The string xxxxxx is replaced with the hex codes for the three bytes sent in the information part of the FRMR frame This message wil...

Page 212: ...f ROM 64K 1 x 27C512 Standard complement of system AM 32K 1x 43256C 15L Standard complement of mailbox RAM 0K expandable to 32K 128K or 512K Serial Z8440 SIO 0 port B configured as UART plus low power...

Page 213: ...provided Full duplex radio link operation is supported Packet Command Mode accepts commands via user port Operating Modes Converse Mode accepts digital data transmits and receives packets permits term...

Page 214: ...the MFJ TNC to remember these values when power is off so you don t have to enter them every time you want to operate Other integrated circuits are used for functions including clock oscillator baud r...

Page 215: ...as well as the radio channel baud rate The output from counter U1 at pin 12 provides a real time clock interval signal for the SIO During normal operation the SIO will be programmed to interrupt the...

Page 216: ...bility with the AX 25 protocol specification Latch U5 and ROM U6 provide a state machine for recovering the clock from the received NRZI data The state machine also converts NRZI data to NRZ for the S...

Page 217: ...are measured by the calibration software and the output signal produced by U8a and U8b which is a frequency doubling shaping circuit Power Supply Regulator Q3 and associated components provide a 5 vo...

Page 218: ...ignored by the software if software flow control is enabled in this direction The MFJ TNC asserts its Clear To Send CTS output J1 pin 5 whenever it is ready to receive data from the terminal If the M...

Page 219: ...modem or another TNC a so called null modem cable may be constructed to interchange the data and handshake signals Jumper Functions The following table lists the function of each jumper on the MFJ TN...

Page 220: ...TTL RTS enable OFF TTL RTS disable JMP17 Pin1 2 2400 baud ext modem clock Pin 2 3 default 9600 baud ext modem clock JMP18 Pin 1 2 default Enable 19 2K baud termial Disable 300 baud terminal Pin 2 3 E...

Page 221: ...have to reset the clock everytime you turn the MFJ TNC on MFJ provides the user with a TTL Level Input Output port This port is usable with computers which cannot make use of the Serial Input Output R...

Page 222: ...m directly to J4 NOTE The modem disconnect is similar but not identical to that used in TNC 1 Be very careful about interfacing an external modem using the same cabling you may have prepared for use w...

Page 223: ...n board modem It activates the PTT pin of the radio connector via the watch dog timer It should be left high and pulled low only when transmission is desired This pin is normally jumpered to pin 5 whe...

Page 224: ...desired radio port data rate This pin is normally jumpered to pin 11 when the on board modem is used Pin 13 Receive Clock Input This pin is tied to the SIO receive clock input pin It expects a clock...

Page 225: ...used Pin 20 Transmit Data Input This input line accepts data to be be transmitted by the modem This pin is normally jumpered to pin 19 when the on board modem is used If you elect to use an off board...

Page 226: ...ry careful about shorting pins on ICs when applying meter or scope probes to the board It is a good idea to attach a secure ground lead to the meter or scope one that won t accidentally short across c...

Page 227: ...U and the Z80 SIO They generally are warm to the touch In general their normal temperature will be well below the boiling point of water but you may not want to keep your finger on them very long Step...

Page 228: ...processor U22 is pin 6 The input clock should be a possibly distorted square wave signal Verify that the clock input at pin 6 of U22 is running at the correct frequency near 4 9152 MHz Verify that the...

Page 229: ...connected to the lines you are measuring If you suspect a short check the high density areas of the PC board for the problem In most cases the short will be found there It is very unlikely that the P...

Page 230: ...25 between high and low tones Note Make sure that JMP 8 is ON Terminal Interface Troubleshooting If you can t get the MFJ TNC to sign on and accept data from your terminal or computer the problem may...

Page 231: ...gibberish verify that the terminal is set to the MFJ TNC s baud rate and do a power off then on cycle on both the MFJ TNC and terminal If the message still fails to appear try troubleshooting with an...

Page 232: ...g to any commands This may be due to some invalid parameters having been stored in the memory Try turning the MFJ TNC off and disconnect JMP 5 on the MFJ TNC board This will disconnect the memory back...

Page 233: ...d software architecture is organized in accordance with the International Standards Organization ISO layered network model The model describes seven levels and is officially known as the ISO Reference...

Page 234: ...vel Data Link Control protocol defined by the ISO HDLC Frames Exact knowledge of the format of HDLC frames has been made largely unnecessary by the advent of LSI and VLSI communications chips which in...

Page 235: ...bit as a transition in the encoded bit stream and a 1 data bit as no transition This in combination with the bit stuffing which ensures that no more than five 1 s occur in a row except when FLAG bytes...

Page 236: ...s The following table lists the frame types used by AX 25 and describes their purpose This material is provided to give a general understanding of the protocol and is not intended to replace the publi...

Page 237: ...cted to be received from the other end of the link RR Usually used to acknowledge receipt of an I frame The RR function can also be performed by sending an I frame with an updated expected next frame...

Page 238: ...frequency and transmits only if there is no carrier The RF carrier is not normally detected however an input is available on the MFJ TNC radio interface connectors to allow such an input In order to...

Page 239: ...milar to that of other stations on the channel One other factor must be taken into consideration in optimizing data throughput The currently implemented link protocols provide for relaying digipeating...

Page 240: ...a TNC transmitting data received from the serial port over the link runs out of temporary buffer space the serial port will be halted by an XOFF character or CTS signal In the MFJ TNC implementation t...

Page 241: ...MFJ 1270C 1274C MANUAL APPENDIX A RADIO HOOKUP Page 232...

Page 242: ...Tip Sm Tip Lg Sleeves YAESU 4 pin Pin 2 Pin 3 Speaker Pin 1 8 Pin Pin 8 Pin 6 Speaker Pin 7 FT 208 HTs Pin 1 Pin 3 Pin 2 Pin 4 FT x09 HTs Tip Sm Tip Sm Tip Lg Sleeves FT x3 HTs FT 727 HTs Table A 1 H...

Page 243: ...y probe at JMP 9 pin 1 This is the top pin 5 Place the oscilloscope probe on top pin of JMP 10 6 Set dip switch 6 ON 7 Set one of the dip switches 1 thru 5 to the Computer Baud Rate which appiles to t...

Page 244: ...st R78 to where the frequency counter indicates 1200 Hz 2 Hz 13 Press the SPACE BAR until pin 9 of U16 indicates 5 VDC 14 Adjust R77 to where the frequency counter indicates 2200 Hz 2 Hz 15 Press the...

Page 245: ...anual the exact configuration of your radio s filters and whether it has IF shift or not will determine the exact required center frequency for the modem Once the required center frequency has been de...

Page 246: ...slightly This is normal 15 Type a Q This exits the MFJ TNC from calibrate mode to command mode This completes the modulator tone alignment using the built in calibration facility If you had any probl...

Page 247: ...r so that it correctly indicates when a signal is properly tuned in relation to the demodulator center frequency In order for the Tuning Indicator to be properly aligned the above calibration must be...

Page 248: ...cation Map This is a map of the physical locations of the adjustment potentiometers on the MFJ TNC circuit board They are shown as they appear when looking down on top of the board with the board orie...

Page 249: ...29 R105 170 Hz shift 1300 404 R78 Packet Fc 1700 Hz 800 Hz shift CCITT V 23 std preferable for HF 1200 baud works 2100 250 R77 well on VHF FM too 1200 438 R78 Packet 1000 Hz shift standard Too wide to...

Page 250: ...set the MFJ TNC to VHF packet mode by setting S1 to the VHF IN position 2 Set dip switch 7 on SW3 to the ON position Set the correct terminal baud rate on SW3 according to the baud rate you are runni...

Page 251: ...ge 242 10 Press the space bar and again measure the peak to peak voltage at J9 pin 4 The audio level should not change Both mark and space audio should be at the same level 11 Remove the jumpers from...

Page 252: ...rol if one is present is in its proper position centered or on detente 7 Record the frequency indicated by the counter The counter should indicate the average frequency of the noise spectrum passed by...

Page 253: ...h 10 Calculate the required modem center frequency as Fc F low F high 2 Once the required center frequency has been determined the modem calibration can be carried out NOTE It is essential that the mo...

Page 254: ...active thru put frequencies these two commands should be reduced to their original settings You may find that if you were using a TXD of 50 then a TXD of 40 will now perform better The DWAIT can be s...

Page 255: ...el then you may adjust the audio level going into your radio by using the Transmit Audio controls on the left side of the MFJ TNC Note that these controls set the transmit audio levels for all the ope...

Page 256: ...per Function Jumper Position Function JMP1 Pin 1 2 DCD RS 232C stays on Pin 2 3 DCD RS 232C stays off OFF default DCD reflects connect status JMP2 Pin 1 2 default 4 92 MHz CPU clock Pin 2 3 2 46 MHz C...

Page 257: ...PJ ON TX audio has flat response OFF default TX audio 6db oct pre emphasized JMPL ON OFF default TX audio loopback to PTT for Radio Port J9 JMPR ON OFF default Analog audio loopback for Radio Port J9...

Page 258: ...MFJ 1270C 1274C MANUAL APPENDIX F JUMPERS Page 249 Fig G 1 Jumper Connector Location...

Page 259: ...l line input editing command character 6 26 CANPAC n 19 Y Packet Changes the cancel packet inputediting command character 6 27 CBELL ON OFF off Packet Sends bell tone to computer or terminal speaker w...

Page 260: ...er which will be output when an escape character is to be sent 6 56 FIRMRNR ON OFF on Packet Controls the handling of busy states by MFJ TNC 6 58 FLOW ON OFF on Packet Sets type in flow control to the...

Page 261: ...nes whether monitored packets containing non printable characters are monitored or discarded 6 77 MONITOR ON OFF on Packet Enables packets that are not6 78 addressed to you to be displayed MRPT ON OFF...

Page 262: ...to be sent in CONVERSE mode 6 110 SLOTS nn 3 Packet Determines how many sides are on the slot time dice 6 112 START n 11 Q All Selects the user restart character 6 114 STOP n 13 S All Selects the use...

Page 263: ...ll1 CQ Packet Sets the digipeat and destination address fields of packets sent in the unconnected mode 6 130 USERS n 1 Packet Controls the manner in which the incoming connect requests are handled 6 1...

Page 264: ...MFJ 1270C 1274C MANUAL INDEX Chapter 16 Page 29...

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