manualshive.com logo in svg

Multitech MMH900, User Manual

Share
Download
Multitech MMH900 User Manual Download Page 115

115

Chapter 7 - Troubleshooting Procedures

8.5

Repair Procedures for International
Distributors

Procedures for International Distributors of Multi-Tech products are
on the distributor web site.

http://www.multitech.com/PARTNERS/login/

8.6

Online Warranty Registration

If you have access to the World Wide Web, you can register your
Multi-Tech product online at http://www.multitech.com/register/.

Summary of Contents for MMH900

Page 1: ...MMH900 Series Statistical Multiplexer User Guide...

Page 2: ...rthermore Multi Tech Systems Inc reserves the right to revise this publication and to make changes from time to time in the content hereof without obligation of Multi Tech Systems Inc to notify any pe...

Page 3: ...5 6 Operational Statistics and Auto Reporting 19 1 5 7 Parameter Memory 19 1 5 8 Channel Flexibility 19 1 5 9 Command Modem 19 1 5 10 Composite Link 20 1 6 FCC Regulations for Telephone Line Interconn...

Page 4: ...ctor 41 3 4 9 CHANNEL 1 CHANNEL 8 Connectors 41 3 5 Switches Jumper Shunt 42 3 5 1 8 Position DIP Switch 42 3 5 2 4 Position DIP Switch 43 3 5 3 144RKWL OtherJumper 44 3 5 4 V 24 V 35 Shunt 44 3 5 5 V...

Page 5: ...5 Channel Device Testing 107 7 6 Local Modem and Communications Line Testing 108 7 7 MultiMux Functional Testing Procedures 110 Chapter 8 Service Warranty Technical Support 112 8 1 Introduction 113 8...

Page 6: ...6 Local Analog Loopback Test Sync Mode 157 I 7 Digital Loopback Test Loc Man Sync Mode 158 I 8 Digital Loopback Test Rem Auto Sync Mode 159 Appendix J Internal MMH2834 Composite Link Modem Commands 16...

Page 7: ...Chapter 1 Introduction Description...

Page 8: ...V 2 9 V 3 3 RCV Channel one RCV XMT CD RCV XMT CTS V 35 XMT RCV XMT RCV XMT XMT RCV XMT RCV I N T E R N A L L I N K D E V I C E M o d e m s Systems MultiT ech M M H 2 8 3 4 CD I S D N ISDN Figure 1 1...

Page 9: ...uration Chapter 5 Commands The MultiMux is software driven and controlled through its command port and the supervisory console This chapter describes the AT commands and the impact each has on your sy...

Page 10: ...mple Communications Network One reason that a stat mux works is that typically an asynchronous terminal device is not used to its capacity Studies show that as little as 10 to 15 utilization of such l...

Page 11: ...tical Multiplexing Statistical multiplexing is sometimes referred to as statistical time division multiplexing STDM The use of the voice grade phone line or any other communications link is based not...

Page 12: ...and the MultiMux is made through an RS232 interface cable Asynchronous modems long haul or short haul asynchronous modem emulators and asynchronous line drivers DCE devices can be used in this connec...

Page 13: ...ed to four async devices on CHANNEL 1 through CHANNEL 4 The workstation connected to the COMMAND PORT is the supervisory console in which you can communicate with the command processor or command mode...

Page 14: ...DIP switches behind the front panel and software commands entered through the supervisory console The DIP switches determine whether the MultiMux is a four or eight channel multiplexer whether the com...

Page 15: ...of device used as the composite link device is determined by whether the device is internal or external which is established by a DIP switch setting and by the type of device installed in the MultiMu...

Page 16: ...amount sent with each transmission This insures that interactive users will not experience undue delays but on the other hand batch activity can still be accommodated This combined with a Response Ti...

Page 17: ...y aspect of the network The diagnostics include easy to execute tests for each channel the composite link and for various components of the MultiMux unit itself There are nine different test modes to...

Page 18: ...bility The MultiMux permits a great deal of flexibility in configuring channel parameters You can mix up channel options including speed word length stop bits parity flow control pacing methods echoes...

Page 19: ...connected internally and externally Internally the MultiMux can be configured with synchronous lease line modem at a link speed up to 28 8K bps or a Data Service Unit DSU at link speeds up to 56K bps...

Page 20: ...one company to determine the maximum REN for the calling area 4 If this equipment causes harm to the telephone network the telephone company will notify you in advance But if advance notice isn t prac...

Page 21: ...mission or corporation commission for information 9 If required this equipment is hearing aid compatible Manufacturer Multi Tech Systems Inc Model Number MMH904 MMH908 FCC Registration No AU7USA 73205...

Page 22: ...epairs to certified equipment should be made by an authorized Canadian facility designated by the Supplier Any repairs or alterations made by the user to this equipment or equipment malfunctions may g...

Page 23: ...Xoff Interface RS232C CCITT V 24 25 pin female D connectors 1 8 2 System Control Local Access Through MultiMux s RS232C Command Port Remote Access Through MultiMux s internal dial up CCITT V 22bis V...

Page 24: ...n ITU T V 34 AT T V 32 terbo ITU_T V 32bis V 32 V 22bis Bell 212A and 103 North America or B 23 and V 21 international Speeds 300 bps tp 33 6K bps Commands Fully AT command compatible Usage Synchronou...

Page 25: ...l ISDN 1 NEC International Switch Line Interface 2 wire ISDN Basic Rate 2B1Q U interface ANSI T1 601 1992 compliant RJ 48 jack B Channel Aggregation BONDING Protocol Mode 1 1 8 7 Command Modem Descrip...

Page 26: ...Chapter 2 Configuration...

Page 27: ...local AT command configuration information The configuration of the MultiMux MMH900 series is as follows Model Description MMH904Ca Four channel unit with internal command modem MMH908Ca Eight channe...

Page 28: ...ration 1 Channels 1 through 4 at the local site are connected to channels 1 through 4 at the remote site The asynchronous channels of the local mux are configured with XON XOFF software flow control e...

Page 29: ...OFF OFF OFF OFF 04 19200 8 1 NONE XON XOFF OFF OFF OFF OFF OFF OK Configuration 1 Local Site Channel Parameters Local Channel Parameter STP FLOW ENQ PASS PASS CHN SPD WORD BIT PARITY CONTROL ACK ECHO...

Page 30: ...ity of the data over the link The MultiModemIIs are set up for data compression and error correction in order to achieve the link speed Figure 2 2 Configuration 2 The External Composite Link LEDs on t...

Page 31: ...nected to the MMH908Ca 56s at the INTERNAL COMPOSITE LINK DIGITAL DSU connector on the back panel of the MultiMuxes The composite link is set for DDS clocking Figure 2 3 Configuration 3 The INTERNAL L...

Page 32: ...0 8 1 NONE XON XOFF OFF OFF OFF OFF OFF 08 19200 8 1 NONE XON XOFF OFF OFF OFF OFF OFF OK Configuration 3 Local Site Channel Parameters Local Channel Parameter STP FLOW ENQ PASS PASS CHN SPD WORD BIT...

Page 33: ...Chapter 3 Front Rear Panel Descriptions...

Page 34: ...a channel device or using the supervisory console The front panel indicators are divided into four main categories the Command Modem External Composite Link device Internal Composite Link device and t...

Page 35: ...ries is configured for an external composite link device and a carrier signal is detected RCV XMT The Transmit XMT and Receive RCV indicators are used when the MultiMux MMH900 series is configured for...

Page 36: ...emote multiplexer RCV The Receive RCV indicator flashes as data is being received by the MMH2834 modem from the remote multiplexer CTS The Clear To Send CTS indicator lights when the MMH2834 composite...

Page 37: ...lights when the MultiMux has data it wants to transmit over the composite link NS The No Signal NS indicator lights when no signal at all is received from the DDS line or when the signal is too weak...

Page 38: ...RCV The Receive RCV indine line or modem problem Steady when buffer overflow conditions exist REMOTE DWN The local mux cannot establish communications with the remote mux TEST MODE A device in the net...

Page 39: ...n the down position 3 4 2 Power Connector The power connector is a receptacle for a 3 prong grounded power cord 3 4 3 COMMAND MODEM DIAL UP Connector This connector is used when the command modem is c...

Page 40: ...ernal DSU is installed This connector provides an RJ48 connection to the DDS or dedicated network 3 4 8 COMPOSITE LINK EXTERNAL RS232C V 35 Connector This connector is used when an external modem or D...

Page 41: ...osition DIP Switch Power Supply V 35 Shunt V 24 Shunt V 29 V 33 Shunt 2834 Shunt Figure 3 3 Base 3 5 1 8 Position DIP Switch The 8 position DIP switch is shown in Figure 3 3 and the function of each p...

Page 42: ...h an MMH908 Unit Channel 1 8 9 16 17 24 25 32 Switch Position 6 C O C O Switch Position 7 C C O O Switch Position 8 C C C C 3 5 2 4 Position DIP Switch The four position DIP switch determines the type...

Page 43: ...er an RS232C V 24 or a V 35 interface can be connected to a MultiMux MMH900 series When an external composite link device with an RS232C V 24 interface is connected to the MultiMux the V 24 shunt shou...

Page 44: ...Chapter 4 Installation...

Page 45: ...ck from lightning 6 Do not use the telephone to report a gas leak in the vicinity of the leak 4 3 Unpacking Unpack and check all the items in the MultiMux shipping list to ensure that you have receive...

Page 46: ...inal adapter Connect the Mux Converter cable supplied with the unit to the COMPOSITE LINK INTERNAL DIGITALconnector on the back panel of the MultiMux and your phone line MultiMux is being connected to...

Page 47: ...MultiMux to the AC power connector on the back panel and to the AC outlet 3 Press the power ON OFF switch on the back panel of the MultiMux to apply power 4 If the internal composite link modem is V...

Page 48: ...ANNEL 2 CHANNEL 5 CHANNEL 1 COMMAND PORT COMMAND PORT Figure 4 3 Supervisory Console Cabling 6 Apply power to the supervisory console and enter AT and then hit Return If you get an OK message back you...

Page 49: ...3 CHANNEL 6 CHANNEL 2 CHANNEL 5 CHANNEL 1 Channels Figure 4 5 Channel Cabling 9 Execute the parameter display command to display the current channel parameter status for your local MultiMux by enterin...

Page 50: ...50 Chapter 4 Installation As you change operational parameters they will not actually be incorporated into your running system until you execute a Store New Parameters W command...

Page 51: ...Chapter 5 Commands...

Page 52: ...nnel 1 The following command changes the baud rate to 4800 bps parity to odd CTS flow control and turns echo off ATC1B4800P2F1E0 Table 5 1 presents a summary of all the commands used in the MultiMux T...

Page 53: ...ntrol Off F1 CTS RS232C Flow Control F2 Xon Xoff Flow Control F3 Enq Ack On F4 EnqAck Off F5 Pacing On F6 Pacing Off F7 Pass EIA RS232C Signals On F8 Pass EIA RS232C Signals Off F9 Xon Pass Thru On F1...

Page 54: ...ameters S1 8 Channel Status Reports Composite Link C Clear Composite Statistics CLA Composite Link Access F Load Factory Defaults for DSU and ISCC FT Flush Timer Value L List Composite Link Configurat...

Page 55: ...m Configuration M ASYNC SYNC MMH2834 Sync or Async Mode M DIAL LEASED Dail up or leased line MWIRE 2 4 2 or 4 wire leased line MTL 0 10 Transmit Level 0 or 10 db M ANSWER ORIGINATE Lease Line Answer o...

Page 56: ...56 Chapter 5 Commands Table 5 1 Command Summary cont TYPE COMMAND DESCRIPTION Command Modem MA Command Modem Select RA Remote Command Modem Access...

Page 57: ...Prior to executing the W command any changes to MultiMux parameters are temporary and do not affect the unit s operation until you execute the W command followed by a reset Z command The W command sto...

Page 58: ...y one of the command letters ATH1 for channel parameter commands ATH2 to view the DIP switch configurations ATH3 for async and sync composite link format commands ATH4 for additional composite link co...

Page 59: ...NODE SELECTION SN LOCAL SOURCE NODE NUMBER E LOCAL ECHO S CHANNEL STATISTICS F FLOW CONTROL SL SELECT LOCAL PARAMETERS F READ IN FACTORY DEFAULTS SR SELECT DOWNLINE LOAD PARAMETERS L LIST PARAMETERS W...

Page 60: ...DN OFF EXTERNAL 4 CHAN DISABLED CURRENT SETTINGS DN DN DN DN DN DN DN DN 1 4 5 8 9 12 13 16 17 20 21 24 25 28 29 32 SW 6 DN UP DN UP DN UP DN UP SW 7 DN DN UP UP DN DN UP UP SW 8 DN DN DN DN UP UP UP...

Page 61: ...S SELECTED SYNC SELECTS SYNC COMPOSITE LINK ASYNC SELECTS ASYNC COMPOSITE LINK For HELP on a specific command enter ATH followed by the command letter EXAMPLE ATH MUXCL ENTER The H4 Menu is as follows...

Page 62: ...WRITE TO MEMORY Z RESET MULTIMUX For HELP on a specific command enter ATH followed by a command letter The H6 Menu is as follows Commands to configure the MultiMux Internal V29 V33 modem CQ CABLE EQUA...

Page 63: ...etter The H8 Menu is as follows INTERNAL MMH2834 COMMANDS M ASYNC SYNC SYNC OR ASYNC M DIAL LEASED DIAL UP OR LEASE LINE MWIRE 2 4 2 OR 4 WIRE LEASE LINE MMTL 0 1 TRANSMIT LEVEL 1 OR 10DB M ANSWER ORI...

Page 64: ...nto all the channels This allows you to change such conditions as baud rate word length parity and flow control on all channels by executing a single command C1 C8 Channel Select The Channel Select co...

Page 65: ...ber a node where its SN command was SN01 you can communicate with the 01 location channels by executing a DN01 command At that point your local channels will communicate with those at node 01 The spec...

Page 66: ...x F3 F4 ENQ ACK Flow Control These two commands control the selection of a special flow control system used in Hewlett Packard computer systems It is sometimes referred to as Enquire Acknowledge flow...

Page 67: ...MultiMux B F9 F10 PassXon Xoff The Pass Xon Xoff commands F9 enable F10 disable are active only if Xon Xoff flow control is active Also called the Pass Through commands they enable or disable the Mult...

Page 68: ...ng F13 causes the MultiMux to stop data flow to the channel device upon receipt of a Xoff Character The next character from the channel device will start data it does not have to be an Xon Character F...

Page 69: ...channel devices The P0 command turns parity off P1 sets odd parity and P2 setsit at even R Response Time Priority The Response Time Priority command determines how long the mux will wait to send data...

Page 70: ...MultiMux32 model The SN command specifies the node number of the local node This number is determined by you and can be any decimal number up to 255 It should be assigned when you are designing your...

Page 71: ...the execution of this command all other commands will act on the local parameter set An W command stores the parameters When power is turned on the local parameter mode is in effect SR Select Downlin...

Page 72: ...The status message is displayed in the following format STATISTICS FOR CHANNEL NUMBER XX RECEIVE FLOW CONTROL TIME 00 HRS 00MIN 00SEC BUFFER UTILITZATION 00 EIA STATUS FLOW CONTROL REQUEST SENT NO PAC...

Page 73: ...atistics command clears the composite statistics record without resetting the entire MultiMux unit F Load Modem Default The Load Modem Default command returns the status of the internal composite link...

Page 74: ...composite link DSU MODEM TXMIT RECV CABLE LINK LINK T 2 ECHO TEST CONFIGURE LEVEL LEVEL EQU AMP DELAY EQU PROT MODE V29 9600 0DB 43DB 0 0KM OFF OFF T2 OFF OFF MODEM TXMIT RECV CABLE LINK LINK T 2 ECHO...

Page 75: ...0bps RT0 99 Status Report Time This command sets the time interval in hours at which the status report generated by the S0 command is displayed on thesystem supervisor console display The intervals ar...

Page 76: ...TS 0 BLOCKS RECEIVED 0 RECEIVE BLOCK ERRORS 0 LINK ALARMS 0 REMOTE DOWNS 0 RECEIVE FLOW CONTROL TIME 00 HRS 00 MIN 00 SEC AUTOMATIC REPORTING OFF 19200 BAUD S9 LED Status This command displays the Mul...

Page 77: ...link is in Async mode the EOFTxx command determines the End of Frame character by the hexadecimal value of xx The Transmit End of Frame Character should only be set under the direction of Tech Suppor...

Page 78: ...l clocking the Mux Speed command sets the speed of the composite link If the composite link is in synchronous mode and external clocking is used the Mux Speed command is not used The default condition...

Page 79: ...t to the composite link The default condition is no access to the composite link thru the command port DTR Toggle DTR The Toggle DTR command DTR drops DTR for 500 msec on the composite link The Toggle...

Page 80: ...by the modem With an echo protect tone present the modem will send a tone on the line prior to connection The EP0 command shuts off echo protection on the line This parameter should be changed only u...

Page 81: ...o that the lower frequencies are attenuated less than the higher frequencies The longer the cable the more pronounced the effect Each of these commands will compensate for the effect according to its...

Page 82: ...L6 12 dbm TL7 14 dbm T1 2 T Level This command selects the type of adaptive equalizer used by the receiver In most cases a two taps per baud spre ad over 16 bits gives the best performance because of...

Page 83: ...link line the MMH2834 is set for The MDial command places the MMH2834 modem in a dial mode The MLeased command places the MH2834 modem in lease line mode The default is dial up mode MWire 2 4 Interna...

Page 84: ...s access from the command port to the composite link The default condition is for access enabled thru the command port to the MMH2834 MTR Internal MMH2834 Modem Data Transmission Rate 28800 19200 1440...

Page 85: ...DS Network s Receive Bipolar Signal DDS Clocking command DSUCLD is used whenever the internal DSU is connected to DDS network line The DSUCLD command is the factory default and automatically configure...

Page 86: ...supervisory console If the test fails a RAM address is given and the read and write values are shown T3 Not used T4 Test Mode 4 Test Mode 4 is the Analog Loop test which checks the operation of a loc...

Page 87: ...s and verify that they work by corresponding LEDs being lit T8 Test Mode 8 Test Mode 8 is the Non Volatile Memory test Its function is to check the proper operation of the MultiMux s battery backed st...

Page 88: ...A1 command enables the command modem The MA0 command disables the command modem input and hangs up the phone line RA Remote Command Modem Access The Remote Command Modem Access RA1 command allows comm...

Page 89: ...Chapter 6 Operating Procedures...

Page 90: ...status for your local MultiMux by entering the following ATL hit Return The following will be displayed on your supervisory console Local Channel Parameter STP FLOW ENQ PASS PASS CHN SPD WORD BIT PARI...

Page 91: ...nonvolatile memory and become effective immediately When power is turned off the parameters will be saved Composite Link 5 If you wish to display the composite link modem status execute the Modem Disp...

Page 92: ...mposite Link Device DSU LED is ON 5 cont Based on the listed modem status conditions reconfigure the parameters to the conditions required in your particular installation by entering the appropriate I...

Page 93: ...unit An MMH904 MMH908 unit cannot down line load parameters to an MM16 MM32 or MMH16 MMH32 unit 9 To return to local parameter display and control execute a Select Local Parameter command by entering...

Page 94: ...d in a verbose format complete English words or in a terse format single digit numbers The standard factory format is verbose If you wish to change to terse format enter the Result Code Digit command...

Page 95: ...W ENQ PASS PASS CHN SPD WORD BIT PARITY CONTROL ACK ECHO PACE EIA XON 01 19200 8 1 NONE XON XOFF OFF OFF OFF OFF OFF 02 19200 8 1 NONE XON XOFF OFF OFF OFF OFF OFF 03 19200 8 1 NONE XON XOFF OFF OFF O...

Page 96: ...Chapter 7 Troubleshooting...

Page 97: ...lem before and can help you quickly See Chapter 8 of this manual 7 2 Importance of Composite Statistics The Composite Link Status Command AT S0 provides additional information concerning the operation...

Page 98: ...has sent data 30 times and could not get it through the link has been broken The other entries in the composite status report do not apply to link problems 7 3 Test Cables If you are using the MultiM...

Page 99: ...ternal Composite Connector MultiMux MultiMux Using the Test Cable Using the Composite Link Loopback Cable MultiMux MultiMux Internal Composite Connector Composite Link Loopback Cable Note Used locally...

Page 100: ...onditions may account for a number of different failures the following guide is just that a guide to troubleshooting The parts of your mux network are Channel devices printers terminals pc s etc Chann...

Page 101: ...d RCV LEDs ON and REMOTE DWN LED ON Composite link down with CO CTS and REMOTE DWN LEDs ON Composite link and all channels down with REMOTE DWN and all channel RCV LEDs ON Flashing LINK ALARM LED All...

Page 102: ...ent pins refer to Supervisory Console Installation procedures in Chapter 4 2 Check RS232 cable connections between supervisosry console and COMMAND PORT on MultiMux for correct cable wiring refer to C...

Page 103: ...nnected to communications line 3 If external modems are used verify that they are powered ON and connected to the communication line and Mux composite link Problem Faulty Communication line Solution 1...

Page 104: ...all channel parameters Flashing LINK ALARM LED Problem High error rate on communication line Solution 1 View composite link statistics using S0 command 2 Perform local and remote loopback test refer...

Page 105: ...n 1 Verify channel parameter settings for those channel devices refer to Lx command in Chapter 4 to display channel parameters 2 Perform channel device testing refer to Channel Device Testing in this...

Page 106: ...ltiMux unit in Test Mode 4 i e executing the Analog Loop test by entering the following command If using external modem this test does not apply AT T4 hit Return The supervisory console will display t...

Page 107: ...he setting of the two modems to test the two network segments Table 7 3 Modems and Communications Line Testing Procedure 1 If external modems are used set them to test the desired network segment acco...

Page 108: ...oard of each channel device and if the network is operating correctly the data will be correctly displayed on the channel device monitor If the channel device is equipped with an active local echo fea...

Page 109: ...g the non volatile memory feature enter an ATL command and record all channel parameters 2 Place the MultiMux in Test mode 8 i e executing the non volatile Memory test by entering the following comman...

Page 110: ...command AT T9 hit Return The supervisory console will display the following message Watch Dog Timer Test 9 wait for test indicator to turn off and when the test indicator comes back on enter AT to end...

Page 111: ...Chapter 8 Service Warranty Technical Support...

Page 112: ...ERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE HEREBY DISCLAIMED This warranty does not apply to any products which have been damaged by lightning storms water or power surges or which have b...

Page 113: ...tech com documents warranties Extended two year overnight replacement service agreements are available for selected products Please call MTS at 888 288 5470 extension 5308 or visit our web site for de...

Page 114: ...tact us for return autho rization and shipping instructions on any International shipments to the U S A Please include inside the shipping box a description of the problem a return shipping address mu...

Page 115: ...Procedures for International Distributors of Multi Tech products are on the distributor web site http www multitech com PARTNERS login 8 6 Online Warranty Registration If you have access to the World...

Page 116: ...Appendices...

Page 117: ...52 82 r 72 114 S DC3 13 19 3 33 51 S 53 83 s 73 115 T DC4 14 20 4 34 52 T 54 84 t 74 116 U NAK 15 21 5 35 53 U 55 85 u 75 117 V SYN 16 22 6 36 54 V 56 86 v 76 118 W ETB 17 23 7 37 55 W 57 87 w 77 119...

Page 118: ...ces of all mux circuits which accept signals from the data processing terminal or CPU equipment have DC resistances of 4 7K For more specific details consult the EIA RS232C standard itself The followi...

Page 119: ...ace Specifications The computer or terminal should be supplied with a cable terminated with a Cinch DB25P or equivalent connector mounted in a Cinch DB51226 1 or equivalent hood assembly as specified...

Page 120: ...ut EIA pass Thru PIN NO 1 2 3 4 5 6 7 8 20 22 25 1 2 3 4 5 6 7 8 20 22 25 To MultiMux Channel Connector To DCE Device Communication Device i e Modem CHASSIS GROUND AA TRANSMIT DATA BA RECEIVE DATA BB...

Page 121: ...ROUND AA TRANSMIT DATA BA RECEIVE DATA BB DATA SET READY CC SIGNAL GROUND AB DATA TERMINAL READY CD PIN NO DCE to DTE cabling PIN NO 1 2 3 4 5 6 7 8 20 22 25 1 2 3 4 5 6 7 8 20 22 25 To MultiMux Comma...

Page 122: ...ARRIER DETECT DATA TERMINAL READY TRANSMIT DATAA RECEIVE DATAA TRANSMIT DATA B RECEIVE DATA B EXTERNAL TX CLOCK A RECEIVE CLOCK A EXTERNAL TX CLOCK B RECEIVE CLOCK B TRANSMIT CLOCK A TRANSMIT CLOCK B...

Page 123: ...PIN CONNECTOR FEMALE FG RD TD CTS RTS SG DTR INT CLK DSR DCD TXC RXC DCE DTE This cable is used to connect two muxes back to back during testing The cable is asymmetrical and allows one of the mux s t...

Page 124: ...ted The last command will remain stored in the modem s command buffer until the Attention command AT is entered Therefore AT must not be entered before an A command because the A will have no effect i...

Page 125: ...would enter ATD on your keyboard and hit Return You would then hang up the handset Unless you have a specific need to dial in this manner we recommend you use the first method where the telephone num...

Page 126: ...ing thePhone Line Off Hook You can make the command modem hang up go On Hook or go Off Hook with the H command Entering ATH1 upper case will bring the line Off Hook just as if you had picked up the te...

Page 127: ...method used by rotary dial telephones which involve the timed opening and closing of a line relay Tone dialing is that used by push button Touch Tone telephones and is sometimes referred to as DTMF or...

Page 128: ...esult Code transmissions and ATQ0 or ATQ enabling them If you do not select either method the factory default setting will enable the Result Codes to be sent R Forcing an Answer Tone in the Dialing If...

Page 129: ...format ASCII characters will have to be converted to their decimal equivalents before being entered S Register decimal values can range from 0 to 127 for ASCII characters or from 0 to 255 for numeric...

Page 130: ...elect a method the factory default setting will cause the command modem to use the verbose results The following shows the terse and verbose result codes and a description of each code Terse Verbose D...

Page 131: ...stored profiles and stored telephone numbers are as follows ACTIVE PROFILE B1 E1 H0 Q0 V1 X4 Y0 G0 P0 T4 Y S00 000 S01 000 S02 043 S03 013 S04 010 S05 008 S06 002 S07 030 S08 002 S09 006 S10 014 S12...

Page 132: ...egisters S0 S14 S18 S21 S22 S23 S25 S26 S27 and S28 The W0 command stores the active profile in the NOVRAM at location zero and W1 stores the active profile in location one W0 is the factory default s...

Page 133: ...BUSY result code if a busy signal is detected This feature is useful because it allows the command modem to immediately abandon a call rather than wait the thirty seconds for a carrier signal that wi...

Page 134: ...VRAM and store it in the active configuration area The command mode buffer is cleared after the Z command is executed The ATZ0 command loads profile 0 into the active configuration area and ATZ1 comma...

Page 135: ...If Quiet Answer is detected the dial modifiers following the command are executed If busy is detected the command modem returns a BUSY result code and goes to the hang up process aborting further exe...

Page 136: ...back into Command Mode This can be useful in dialing applications where command modem data transfer is not desired such as voice communications Escape Sequences Entering Command Mode While Still On Li...

Page 137: ...is a read type of register and will seldom if ever be used in normal operation Each time an incoming ring signal is detected S1 will increase its value by one up to a maximum of 255 If you set the val...

Page 138: ...ed key on most keyboards May be set for any ASCII character If a Line Feed character is not desired it may be changed to a nill bit it can not be totally disabled S5 Backspace Character Unit ASCII Cha...

Page 139: ...abort the call Maximum value is 255 seconds S8 Pause Time for Comma Unit 1 second Range 0 255 Default 2 Description Sets the length of the pause caused by a comma inserted in a dialing command The co...

Page 140: ...95 Description S11 defines the speed of the tone dialing The default value is 95 units Decimal 95 where each unit is one msec meaning that each tone will be on for 95 mSec with a 95mSec pause between...

Page 141: ...active before it will enter the sleep mode The range of S24 is 0 to 255 The Sleep Mode Inactivity Time is automotically set to 5 seconds and Sleep Mode is inhibited when S24 255 S25 Detect DTR Change...

Page 142: ...omething the mux does to the channel device while pacing is something the channel device does to the mux DATA DATA CHANNEL DEVICE INITIATED PACING Channel Device Channel Device Mux Mux MUX INITIATED F...

Page 143: ...rol In the example below the flow control on the minicomputer works as follows 1 2 3 4 5 6 7 8 Mux Link Channel Mini Computer A B C D mux process data to the link mux buffers full mux buffers empty mu...

Page 144: ...Prints Data Print Data Printer Ready Pace on A Print data volume from the mini is appropriate for the printer to process and print it B The printer cannot handle any more data due to its buffers being...

Page 145: ...5 Default 1 Description S0 defines the number of rings the modem waits before answering an incoming call The default value is one ring Decimal 1 which means that the modem answers the call immediately...

Page 146: ...seconds to reset in which case you should increase the value of S8 S11 Tone Dialing Tone Spacing and Duration Unit 1 mSec Range 1 255 80 255 80 255 Default 70 80 80 Description S11 sets the speed of t...

Page 147: ...toral Unit 30 minutes Range 10 255 Default 30 minutes Description When the MMH2834 is in dial back up mode it periodically checks the lease line to see if it is operational and tries to restore the le...

Page 148: ...e between the MMH2834s to establish the Carrier again If the retrain fails both MMH2834s originate and answer MMH2834s start their dial back timers The time is determined by S Register S 19 settings T...

Page 149: ...en the loop has been completed the original data entered should match the data received back on your PCs monitor after the test The Local Analog Loopback Test allows you to verify that the modem s tra...

Page 150: ...3 Once you receive a connect message if responses are enabled enter data from your keyboard For this test typing multiple upper case U characters is a good way to send an alternating test pattern of o...

Page 151: ...f Type AT in Terminal mode hit ENTER dial remote modem establish On line mode enter escape sequence type ATU3 and hit ENTER UUUUU UUUUU Computer or Terminal Local MultiModem Remote MultiModem Computer...

Page 152: ...the local modem will enter its analog receiver be converted to digital data be reconverted into analog and then looped through its transmitter back to the remote modem Your modem passes this test if t...

Page 153: ...k mode Data from your computer or terminal are transmitted through your modem and over the phone line to the remote modem where they are then looped back to your modem See Figure I 3 UUUUU UUUUU Type...

Page 154: ...o On line mode 5 Type data from your keyboard For this test typing multiple upper case U characters is a good way to send an alternating test pattern of ones and zeros The data received by the remote...

Page 155: ...ing tests must be run with your modem in Synchronous mode The test procedures for Synchronous mode are different from those for Asynchronous mode In Synchronous mode you cannot access the modem s AT c...

Page 156: ...AT M1U This first switches your modem from asynchronous to synchronous mode and places it into the Analog Loopback Originate mode The modem is now out of the Command mode and in the pseudo On Line mod...

Page 157: ...the remote modem s receive circuit multiple upper case U characters in Figure I 5 First make certain that you are set up for Synchronous operation by displaying the composite link configuration and e...

Page 158: ...est results in a mismatch of entered received data multiple upper case U characters in Figure I 6 the Local Analog Loopback Test should be performed on both the remote and local modems If that test is...

Page 159: ...D DESCRIPTION MMH2834 Modem D Dial Dial A or Continuous Redial Section J 1 1 D DTR Dialing N Dial a Stored Number MMH2834 Modem P T Pulse Tone Dialing Modify Dialing P Set Pulse Dial Ratios Procedures...

Page 160: ...M Off Error L2 LAPM On MNP Off Correction L3 Direct LAPM Phase Out Handshake Section J 1 8 A Auto Reliable Buffering F Enable Disable Auto Reliable Fallback Character R Retransmit Count E Error Correc...

Page 161: ...sign S Register Values Appendix G MMH2834 CBN Passwords for Callback Phone Numbers Remote DB Callback Security Enable Disable Configuration I Change LOGIN Password Callback RCBNxx Erase Password Secur...

Page 162: ...Continuous Redial If you select the Wait For Dial Tone method of dialing see A or X3 or X4 command you can command the MMH2834 to continuously redial up to 10 redials for DOC units a busy number until...

Page 163: ...nto the modem from the D terminal or computer to which it is connected on pin 20 of the RS232C interface In DTR dialing the modem automatically dials a stored number as soon as it receives a high DTR...

Page 164: ...now compatible with tone dialing Since that is the faster method you will probably choose the tone method for your dialing An example of combining pulse and tone dialing could involve a PBX system whe...

Page 165: ...rse the mode of Mode of operation for your modem from originate to answer or Operation answer to originate so that it would answer the phone and go into answer mode This command turns off the reversin...

Page 166: ...seconds pass before the rings and silence a NO ANSWER R result code is processed The command is used for accessing a system that does not provide a dial tone For example ATDT5551212 6313550 causes th...

Page 167: ...dial tone error correction Xon Xoff flow control pacing and data compressionenabled the command line would be ATX4 E1 E5 E13 E15DT16126313550N3 This would store the entire command at location N3 Numb...

Page 168: ...ed by the complete dialing command and telephone number as originally entered Simply enter ATL and hit RETURN to display these numbers on your video screen or printer An example of an L command listin...

Page 169: ...efaults configurationsettingsinRAMandthefactorydefaultconfiguration settings in ROM The F8 and F9 commands F define the function of the F command The MMH2834 is shipped from the factory with a pre con...

Page 170: ...ynchronous Transmit Clock Transmit Clock Source in conjunction with the MuxClock MUXCL command Select for the composite link External clocking is the default condition X External clocking is when the...

Page 171: ...g using the Q command ATQ1 disables Q Result Code transmissions ATQ0 or ATQ enables Result Code transmission Regarding No Response Answer you may want the answer mode handled without responses and ech...

Page 172: ...the letter R terse is added to these responses When data compression is used the word COMPRESSED verbose or the letter C terse is added to these responses Result Codes The V command controls whether...

Page 173: ...T 2400 response code sets by including or not including the BUSY and or NO DIAL TONE responses while excluding the DIAL TONE response The X command is used to select which responses are provided Regar...

Page 174: ...dumb dial capabilities X1 Providestheextendedresultcodesandprovides dumb dial capabilities The remaining X commands affect Call Progress and turn on Extended Result Codes X2 Looks for dial tone only...

Page 175: ...off and AT T1 turns Trellis coding on factory default Fallback Modes If line conditions deteriorate the MMH2834 automatically drops When On Line its transmission speed fallback The F command control t...

Page 176: ...ialing The condition of DTR can also be used to cause the modem to reset to its default parameters just as if you had given the modem an ATZ command To do this enter the command AT D3 and hit RETURN T...

Page 177: ...mode the modem still accepts MNP or LAP M L2 Command The L2 Command sets your modem to LAP M error correction and disables MNP This command is for Originate mode only Answer mode still accepts MNP or...

Page 178: ...Nreceived AT F1 FallbacktoNormalmodeifCARRIAGERETURNreceived The factory default is F1 Retransmit Count If errors are received during a Reliable connection the modem re sends the block of data which c...

Page 179: ...nd 5 typically send blocks of 1 to 256 BS characters and LAP M typically sends 128 characters For MNP classes 4 and 5 LAP M reducing the block size to 64 characters may give a smoother flow of data an...

Page 180: ...the attached computer through its RS232C port at a fixed baud rate which can be preselected at 300 1200 2400 4800 9600 19 200 38 400 57 600 or 115 200 bps Speed Conversion When using speed conversion...

Page 181: ...mmand remains the same This provides you with a convenient way to switch the serial port speed and still make it easy to go back to the original speed automatically the next time the modem is powered...

Page 182: ...MH2834 responds with 247 When ATI1 is entered the modem responds with a three digit code indicating the firmware version number When ATI2 is entered the modem responds with MMH2834 Listing Current The...

Page 183: ...n example of L8 listing is shown below ATL8 ONLINE DIAGNOSTICS LINK TYPE V 34 LINE SPEED 28800 SERIAL SPEED 115200 ERROR CNTRL COMPRESS LAPMCOMPRESSED FALL BACK FORWARD LOCALLY ENABLED LINE TYPE DIAL...

Page 184: ...Glossary...

Page 185: ...og Transmission One of two types of telecommunications which uses an analog signal as a carrier of voice data video etc An analog signal becomes a carrier when it is modulated by altering its phase am...

Page 186: ...andle at one time The most common understanding is that a byte consists of 8 binary digits bits because that s what computers PCS can handle A byte holds the equivalent of a single character such as t...

Page 187: ...ensus of the industry and users for a particular aspect of manufacturing CCITT s V and X standards e g V 32 and X 25 are examples of de jure standards Compare with de facto standards Decibel dB A unit...

Page 188: ...l Interexchange Code pronounced eb suh dick An IBM character code used in its mainframe and midrange computers It is an 8 bit code 256 combinations that stores one alphanumeric character or two decima...

Page 189: ...s hardware requires its attention IRQs are numbered so that the device issuing the IRQ can be identified and so IRQs can be prioritized J K Kilobit One thousand bits A unit of measure for digital dat...

Page 190: ...it Contrast with ACK Network A group of computers connected by cables or other means and using software that enables them to share equipment such as printers and disk drives to exchange information No...

Page 191: ...uipment which enables the installer to mount the equipment in an industry standardized enclosure The rackmount equipment is fitted with brackets rather than being packaged in its own enclosure Rackmou...

Page 192: ...tronic switch Twisted pair wiring A type of cabling with one or more pairs of insulated wires wrapped around each other An inexpensive wiring method used for LAN and telephone applications also called...

Page 193: ...Glossary 193 X Y Z...

Page 194: ...odes 174 Basic Result Code 175 Baud Rate Select Bxxxxx Com mand 65 C Cable Equalization Command CQ0 3 82 Cabling Diagrams 121 Calling Card Detect Tones 166 Carrier Detect CD 36 Carrier Detect CD Indic...

Page 195: ...DCxx 65 Diagnostics 18 Dial D 163 Dial Back up DBUP Indicator 37 Digital Data Service DDS 14 Digital Loop Signal T 176 Digital Loopback Test 150 Digital Loopback Test Local Manual Synchrono 158 Digit...

Page 196: ...Link DSU Com mands 86 INTERNAL COMPOSITE LINK LEASED MODEM Connec tor 15 Internal Composite Modem Test T10 88 Inverted DTR Command F11 F12 69 ISDN terminal adapter specifications 26 J no entries K no...

Page 197: ...h 40 Operating Procedures 91 Operational Statistics 19 Originate Mode 178 Out Of Service OOS Indicator 38 P Pacing Control Command F5 F6 67 Parameter Memory 19 Pass EIA Signal Commands F7 F8 67 Pass X...

Page 198: ...statistical time division multiplexing STDM 12 Status Report Time Command RT0 99 76 Status Reporting 94 STDM 12 Stop Bit Command SB1 SB2 71 Store New Parameters Command W 58 Storing Phone Numbers D N...

Page 199: ...33 Indicator 39 W Wait for New Dial Tone W 166 Wait Time for Dial Tone 139 S6 139 Wait Time for Dial Tone S6 146 Watch Dog Timer Test Mode T9 88 Word Length Select Command WL5 8 71 Write Configuration...

Page 200: ...S000315A...

Reviews:

No comments

Brands by name

Popular brands

Load more brands