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Comtech EF Data CDM-550T, Manual

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Forward Error Correction Options 

CDM-550T Satellite Modem 

7–8  

Rev. 

1.3 

However, if uncoded operation is used, there is no way to recognize a data false lock. The 
demodulator will indicate that it is correctly locked, but the data out will not be correct. 
 
 

CAUTION

 

Comtech EF Data strongly cautions users when using uncoded operation. 
If the acquisition sweep width exceeds one quarter of the symbol rate, there 
is a very high probability that the demodulator will false lock. 

 

 
 
As an example, if 64 kbps QPSK uncoded is used, the symbol rate will be half of this 
rate, or 32 ksymbols/second. One quarter of this equals 8 kHz. Therefore,  the absolute 
maximum acquisition sweep range which should be considered is +/- 8kHz. If there is 
any frequency uncertainty on the incoming carrier, this should be subtracted from the 
sweep width. The problem becomes progressively better with increasing symbol rate. 
 
 
COMTECH EF DATA CANNOT BE HELD RESPONSIBLE FOR INCORRECT 
OPERATION IF THE USER DOES NOT ADHERE TO THESE GUIDELINES WHEN 
USING UNCODED OPERATION. 

Summary of Contents for CDM-550T

Page 1: ...Part Number MN CDM550T IOM Revision 1 3 CDM 550T Satellite Modem Viterbi Sequential RS Turbo Installation and Operation Manual For Firmware V1 19 or higher...

Page 2: ......

Page 3: ...4 West 7th Street Tempe Arizona 85281 USA 480 333 2200 FAX 480 333 2161 CDM 550T Satellite Modem Viterbi Sequential RS Turbo Installation and Operation Manual For Firmware V1 19 or higher Part Number...

Page 4: ...pport Department at service comtechefdata com Contact us via the web at www comtechefdata com 1 To return a Comtech EF Data product in warranty and out of warranty for repair or replacement 2 Request...

Page 5: ...ments or Suggestions Concerning this Manual ixix Safety Notices ixix Electrical Safety ixix Fuses ixix Environmental xx Installation xx Telecommunications Terminal Equipment Directive xx EMC Electroma...

Page 6: ...Panel 4 3 CHAPTER 5 CONNECTOR PINOUTS 5 1 5 1 Data Connector 25 Pin D Type Female 5 1 5 2 Alarms Connector 15 Pin D Type Male 5 1 5 3 Remote Control Connector 9 Pin D Type Male 5 1 5 4 Auxiliary Seri...

Page 7: ...Setup 9 2 9 4 Other Considerations 9 2 9 4 1 Baud Rate Accuracy 9 2 9 4 2 Async Character Formats Using 1 5 Stop Bits 9 2 CHAPTER 10 CLOCKING 10 1 10 1 Transmit Clocking 10 1 10 1 1 Internal Clock 10...

Page 8: ...14 SUMMARY OF SPECIFICATIONS 14 1 14 1 MODULATOR 14 1 14 2 Demodulator 14 2 14 3 Automatic Uplink Power Control 14 4 14 4 Data Interfaces 14 4 14 5 Miscellaneous 14 4 14 6 Async Overhead 14 5 14 7 Ap...

Page 9: ...ATENATED RS 2200 200 OUTER CODE 512 KBPS 7 14 FIGURE 7 7 COMTECH EF DATA TURBO PRODUCT CODEC RATE 3 4 QPSK OQPSK RATE 21 44 BPSK RATE 5 16 BPSK 7 15 FIGURE 7 8 DIFFERENTIAL ENCODING NO FEC 7 16 FIGURE...

Page 10: ...operators responsible for the operation and maintenance of the CDM 550T Conventions and References Metric Conversion Metric conversion information is located on the inside back cover of this manual Th...

Page 11: ...EF Data Customer Support Department Safety Notices Electrical Safety The CDM 550T Modem has been shown to comply with the following safety standard EN 60950 Safety of Information Technology Equipment...

Page 12: ...round line and neutral conductors The equipment is not designed for connection to power system which has no direct connection to ground The CDM 550T is shipped with a line inlet cable suitable for use...

Page 13: ...d be made using a good quality coaxial cable for example RG58 U 50 ohm or RG59 U 75 ohm All D type connectors attached to the rear panel must have back shells which provide continuous metallic shieldi...

Page 14: ...other warranty is expressed or implied Comtech EF Data specifically disclaims the implied warranties of merchantability and fitness for particular purpose Exclusive Remedies The remedies provided her...

Page 15: ...FEC are provided as standard Figure 1 1 CDM 550T The modem is compact 1U high and 12 inches deep and consumes only 18 watts It has a front panel VFD display and keypad for local configuration and con...

Page 16: ...sing reserved bytes in the overhead structure Using the Eb No the local modem then adjusts its output power and hence a closed loop feedback system is created over the satellite link A benefit of this...

Page 17: ...aughter card field upgradeable It provides the best level of BER improvement currently available and in Rate 3 4 QPSK mode simultaneously conserves bandwidth 1 3 Compatibility For 1 1 applications the...

Page 18: ...provided in the Version 1 10 firmware 1 Link performance statistics logging A second log has been added independent of the stored events log where the user can choose to record link performance statis...

Page 19: ...t a damage report Keep all shipping materials for the carrier s inspection If the unit needs to be returned to Comtech EFData please use the original shipping container 2 2 Mounting If the CDM 550T is...

Page 20: ...ters The auto sensing AC power supply does not require any adjustments Simply plug in the supplied line cord and turn on the switch on the rear panel 2 4 Select Internal IF Loop Correct operation of t...

Page 21: ...als The resultant I and Q signals are then fed to the QPSK BPSK modulator The carrier is generated by a frequency synthesizer and the I and Q signals directly modulate this carrier to produce an IF ou...

Page 22: ...Functional Description CDM 550T Satellite Modem 3 2 Rev 1 3 This page is intentionally blank...

Page 23: ...sired Rack handles at the front facilitate removal from and placement into a rack Figure 4 1 shows the front and rear panels of the modem Figure 4 1 Front and Rear Panel Vacuum Fluorescent Display Key...

Page 24: ...atus Green No Unit Faults or Traffic Faults Green No Tx Traffic Faults Transmit Traffic Off A Tx Traffic fault exists OR the Tx Carrier is in OFF state Green No Rx Traffic Faults demod and Viterbi dec...

Page 25: ...connector The pinout for the EIA 530 connector is provided in the next section Note that the currently selected interface type is indicated by a small orange LED which is located immediately above the...

Page 26: ...ils for this connector are provided in the next section The Auxiliary Serial connector is an HE1402 3 pin header A suitable mate for this connector is AMP part number 281838 3 with three crimp pins AM...

Page 27: ...113 12 Internal Transmit Clock B Modem to DTE ST B SCT B 114 14 Transmit Data B DTE to Modem SD B SD B 103 15 Internal Transmit Clock A Modem to DTE ST A SCT A DB 114 16 Receive Data B Modem to DTE RD...

Page 28: ...ier Off input 10 No Connection 11 Receive I sample for constellation display 12 Unit Fault Relay Normally Closed 13 Transmit Traffic Relay Common 14 Transmit Traffic Relay Normally Open 15 Receive Tra...

Page 29: ...liary Serial Connector HE1402 3 Pin Header Table 5 4 Auxiliary Serial Connector HE1402 3 Pin Header Pin Description 1 EIA 232 Transmit Data Output 2 Ground 3 EIA 232 Receive Data Input PIN NUMBERING L...

Page 30: ...Connector Pinouts CDM 550T Satellite Modem 5 4 Rev 1 3 This page is intentionally blank...

Page 31: ...ed item digit or field Where this solid block cursor would obscure the item being edited for example a numeric field the cursor will automatically change to an underline cursor If the user were to dis...

Page 32: ...entry being accepted and the user is then returned to the previous menu CLEAR CLR Used to escape from the current operation and return to the previous menu IMPORTANT NOTE The keypad has an auto repeat...

Page 33: ...CDM 550T Satellite Modem Front Panel Operation Rev 1 3 6 3 Figure 6 2 Principle Menu Trees...

Page 34: ...T Monitor This menu branch permits the user to monitor the alarm status of the unit to view the log of stored events and to display the Receive Parameters screen STORE LD Store Load This menu branch p...

Page 35: ...r the satellite so that M C information may be passed to the distant end INTFC Interface This menu sub branch permits the user to define which electrical interface type is active at the data connector...

Page 36: ...the user will be presented with a warning screen CONFIG TX FREQ Frequency Edit the transmit frequency This is accomplished by selecting the digit to be edited using the LEFT RIGHT arrow keys The valu...

Page 37: ...d FEC encoder rate If the user changes the modulation or FEC and the currently selected data rate is then invalid it will be adjusted automatically CONFIG TX FEC TYPE Forward Error Correction If eithe...

Page 38: ...lect Viterbi Sequential Turbo or None using the LEFT RIGHT arrow keys then press ENTER CONFIG TX FEC RATE FEC Rate Any FEC Type Except Turbo Select Rate 1 2 Rate 3 4 or Rate 7 8 encoding rate using th...

Page 39: ...urned off when the demodulator loses lock for a very short period of time the demodulator must be unlocked continuously for a period of 10 seconds before the transmit carrier is inhibited This time in...

Page 40: ...power level then press ENTER If the user selects AUPC and Framed mode is not selected the following menu is displayed CONFIG TX PWR MODE AUPC Pressing either ENTER or CLEAR returns the user to the pre...

Page 41: ...e target Eb No of the remote modem Default value is 3 0 dB and upper limit is 9 9 dB The user should then press ENTER CONFIG TX PWR MODE AUPC MAX RANGE Edit the maximum permitted increase in power lev...

Page 42: ...NFIG TX PWR MODE AUPC DEMOD UNLOCK Select the action that will occur if the remote demod is unlocked The choices are NOM PWR Nominal Power where the ouput level will revert to the nominal power level...

Page 43: ...o the DTE which is derived from its internal high stability source EXTERNAL indicates that the CDM 550T expects to receive a clock from the DTE to which the unit can phase lock its internal circuits L...

Page 44: ...out of the FEC encoder is reversed to make the modem compatible with certain other manufacturer s modems 6 2 3 2 CONFIG RX Receive The sub branches available are CONFIG RX MOD Modulation Select BPSK Q...

Page 45: ...e of the digit is then changed using the UP DOWN arrow keys The user should then press ENTER The overall range of data rates is from 2 4 to 2048 kbps NOTE The minimum and maximum data rates are depend...

Page 46: ...ill be displayed Select Viterbi Sequential Turbo or None using the LEFT RIGHT arrow keys then press ENTER CONFIG RX FEC RATE FEC RATE Select Rate 1 2 Rate 3 4 or Rate 7 8 encoding rate using the LEFT...

Page 47: ...to be edited using the LEFT RIGHT arrow keys The value of the digit is then changed using the UP DOWN arrow keys The user should then press ENTER The range varies from 1 kHz to 30 kHz The value enter...

Page 48: ...cal transmit clock and a small amount 5 clock jitter due to the demodulation bit timing recovery process at low values of Eb No When ON is selected the Plesiochronous Doppler buffer is enabled The inp...

Page 49: ...he same as reversing the direction of phase rotation in the demodulator Note that in BPSK mode the demodulator will automatically synchronize to either the normal time ordering of bits FEC codeword pa...

Page 50: ...which was added in Software Version 1 19 This provides an alternaive to the EDMAC modes described below CONFIG FRAME FRAMED Select either EDMAC OFF or EDMAC ON using the LEFT RIGHT arrow keys then pr...

Page 51: ...stant end modem which this unit will pass messages to This is accomplished by selecting the digit to be edited using the LEFT RIGHT arrow keys The value of the digit is then changed using the UP DOWN...

Page 52: ...ntended to be located at the distant end of a link and will therefore be under the control of a MASTER at the other end This is the equivalent of putting the unit into Remote Control mode no local con...

Page 53: ...or INTERFACE using the LEFT RIGHT arrow keys then press ENTER CONFIG REMOTE BAUD If BAUD RATE is selected Edit the baud rate of the remote control bus connected locally to the M C computer The value i...

Page 54: ...IG REM INTFC ADDR RS232 BUS ADDRESS However if either RS485 mode is selected the user will be further prompted CONFIG REM INTFC ADDR RS485 BUS ADDRESS Edit the RS485 bus address of this unit This is a...

Page 55: ...l being applied will cause compression in the IF stages and hence degrade the performance of the demodulator If the user selects MASKED no alarm will be generated CONFIG MASK Eb No Select either ACTIV...

Page 56: ...t in the receive data If the user selects MASKED no alarm will be generated CONFIG MASK BUF SLIP Buffer slip Select either ACTIVE or MASKED using the LEFT RIGHT arrow keys then press ENTER If the user...

Page 57: ...ansmit Traffic fault will be generated whenever the transmit circuitry senses that the all ones condition is present in the transmit data If the user selects MASKED no alarm will be generated 6 2 3 6...

Page 58: ...onfiguration parameters are temporarily changed to match those of the transmit side When NORMAL is again selected all of the previous values are restored DIG LOOP Digital Loopback This test mode invok...

Page 59: ...CDM 550T Satellite Modem Front Panel Operation Rev 1 3 6 29 Figure 6 2 Loopback Modes...

Page 60: ...NTER 6 2 5 2 INFO TX Transmit information The information displayed here is as follows Top line Transmit Frequency and Data Rate FEC Encoder type VIT Viterbi SEQ Sequential VRS Viterbi Reed Solomon SR...

Page 61: ...er on N off Clocking Mode Demod Sweep Acquisition range RSI state I Receive Spectral Inversion on N off 6 2 5 4 INFO BUFF Buffer information This displays if the buffer is enabled or disabled shows th...

Page 62: ...ormat as the CONFIG MASK sub menu which alarms are currently masked If an alarm is not masked a blank is displayed in the relevant screen position 6 2 5 8 INFO MISC Miscellaneous information This scre...

Page 63: ...IT ALARMS Select UNIT RECEIVE or TRANSMIT using the LEFT RIGHT arrow keys then press ENTER Depending on the choice selected one of the following menus will be displayed MON ALARMS UNIT Unit alarms The...

Page 64: ...the energy per information bit Ebi divided by the noise spectral density No dF The frequency offset of the received carrier in kHz with a displayed resolution of 100 Hz BER This is an estimate of the...

Page 65: ...revious menu The event log can store up to 100 events When a fault condition occurs it is time stamped and put into the log Similarly when the fault condition clears this is also recorded as shown bel...

Page 66: ...the entry Note that in accordance with international convention the date is shown in DAY MONTH YEAR format The bottom line of the display shows the statistics data which has been measured and recorded...

Page 67: ...rval 2 5 dB Average TPLI observed in the measurement interval 1 8 dB LOSS 04 5 0 0 0 0 means There was a loss of demod lock during the measurement interval Average Eb No observed in the measurement in...

Page 68: ...om line shows how much the AUPC system has increased the output power If AUPC is not enabled the value of TX POWER INCREASE will show as 0 0 dB 6 2 7 STORE LD Store Load Select STORE or LOAD using the...

Page 69: ...en is displayed Pressing ENTER or CLEAR will take the user back to the previous menu If however the selected location contains a previously stored configuration the following screen is displayed Selec...

Page 70: ...ocation contains valid data the following screen will be displayed Pressing ENTER or CLEAR will take the user back to the previous menu If however the selected location does not contain valid data the...

Page 71: ...eal time clock This is accomplished by selecting the digit to be edited using the LEFT RIGHT arrow keys The value of the digit is then changed using the UP DOWN arrow keys Note that in accordance with...

Page 72: ...ring of the Plesiochronous Doppler buffer 6 2 8 4 UTIL ID Circuit ID Edit the Circuit ID string using the LEFT RIGHT and UP DOWN arrow keys Only the bottom line is available 24 characters The cursor s...

Page 73: ...mall daughter card and may be fitted at the factory at the time of order or may be added by the user at a later date The second option is Comtech EF Data s Turbo Product Codec which is an entirely sta...

Page 74: ...ed threshold effect fails gracefully Coding gain independent of data rate 7 3 Sequential Although the method of convolutional coding and Sequential decoding appear to be very similar to the Viterbi me...

Page 75: ...must be framed and de framed Additionally Reed Solomon codes are limited in how well they can correct errors which occur in bursts This unfortunately is the nature of the uncorrected errors from both...

Page 76: ...e margin Very small additional bandwidth expansion Significant processing delay 25 kbits not good for voice Easy field upgrade in CDM 550T Adds to demod acquisition time 7 5 Turbo Product Codec Option...

Page 77: ...and high FEC code rates up to Rate 1 3 for example the power spectral density may be reduced Taking Rate 1 2 QPSK as a baseline moving to Rate 5 16 BPSK Turbo Product Coding gives an immediate reduct...

Page 78: ...te 21 44 BPSK 64 Turbo Product Coding Rate 5 16 BPSK 48 Note that in all cases the delay is inversely proportional to data rate so for 128 kbps the delay values would be half of those shown above It c...

Page 79: ...mbiguities When FEC is employed the lock state of the FEC decoder can be used to resolve two of the four ambiguities and the remaining two can be resolved using serial differential encoding decoding H...

Page 80: ...y high probability that the demodulator will false lock As an example if 64 kbps QPSK uncoded is used the symbol rate will be half of this rate or 32 ksymbols second One quarter of this equals 8 kHz T...

Page 81: ...Decoding 1E 9 1E 8 1E 7 1E 6 1E 5 1E 4 1E 3 1E 2 1E 1 1 2 3 4 5 6 7 8 9 10 11 12 Eb No in dB Specification limit Rate 1 2 Coding Uncoded BPSK QPSK Typical Performance Specification limit Rate 3 4 Cod...

Page 82: ...ng 64 kbps 1E 9 1E 8 1E 7 1E 6 1E 5 1E 4 1E 3 1E 2 1E 1 1 2 3 4 5 6 7 8 9 10 11 12 Eb No in dB Specification limit Rate 1 2 Coding Uncoded BPSK QPSK Typical Performance Specification limit Rate 3 4 Co...

Page 83: ...1024 kbps 1E 9 1E 8 1E 7 1E 6 1E 5 1E 4 1E 3 1E 2 1E 1 1 2 3 4 5 6 7 8 9 10 11 12 Eb No in dB Specification limit Rate 1 2 Coding Uncoded BPSK QPSK Typical Performance Specification limit Rate 3 4 Co...

Page 84: ...l Decoding 2048 kbps 1E 9 1E 8 1E 7 1E 6 1E 5 1E 4 1E 3 1E 2 1E 1 1 2 3 4 5 6 7 8 9 10 11 12 Eb No in dB Typical performance Rate 1 2 Coding Uncoded BPSK QPSK Typical performance Rate 3 4 Coding 1 2 3...

Page 85: ...11 12 Eb No in dB Specification Limit Rate 1 2 and 220 200 Outer Code Uncoded BPSK QPSK 1 2 3 4 5 6 7 8 9 10 11 12 BER Viterbi with concatenated RS 220 200 Outer Code Combined sync threshold demod and...

Page 86: ...12 Eb No in dB Specification Limit Rate 1 2 and 220 200 Outer Code Uncoded BPSK QPSK 1 2 3 4 5 6 7 8 9 10 11 12 BER Sequential with concatenated RS 220 200 Outer Code 512 kbps Combined sync threshold...

Page 87: ...9 1E 8 1E 7 1E 6 1E 5 1E 4 1E 3 1E 2 1E 1 1 2 3 4 5 6 7 8 9 10 11 12 Eb No in dB Uncoded BPSK QPSK Comtech Turbo Product Codec Rate 3 4 QPSK Rate 21 44 BPSK Rate 5 16 BPSK 1 2 3 4 5 6 7 8 9 10 11 12 B...

Page 88: ...550T Satellite Modem 7 16 Rev 1 3 Figure 7 8 Differential Encoding No FEC 1E 9 1E 8 1E 7 1E 6 1E 5 1E 4 1E 3 1E 2 1E 1 1 2 3 4 5 6 7 8 9 10 11 12 Eb No in dB Uncoded BPSK QPSK Differential Encoding N...

Page 89: ...tendency for the carefully filtered spectrum to degrade This phenomenon is termed spectral re growth and at the extreme hard limiting the original unfiltered sinx x spectrum would result In most syst...

Page 90: ...of acquisition more difficult The two consequences of this are 1 Acquisition may be longer especially at low data rates 2 The acquisition threshold is higher than for normal QPSK although the demodul...

Page 91: ...n using this mode and the user may have to experiment a little in order to get reliable communication 9 2 ASYNC EIA 232 Specifications Maximum operating baud rate 57 6 kbaud QPSK and OQPSK 28 8 kbaud...

Page 92: ...l device is connected and transmitting data connect a frequency counter to pin 15 of the rear panel Data Connector the 25 pin D type female Measure the frequency then set the transmit frequency to be...

Page 93: ...be the DCE supplies the clock to the DTE The EIA 422 449 name for this signal is Send Timing or ST The DTE then clocks from this source and gives the modem transmit data Send Data or SD synchronous w...

Page 94: ...The CDM 550T incorporates circuitry which permits loop timing when the TX and RX data rates are not the same In this case the clock frequency appearing at ST will be whatever the TX data rate is prog...

Page 95: ...10 4 Loop Timing With Sync EIA 232 The CDM 550T distinguishes between synchronous and asynchronous EIA 232 by detecting clock activity on the TX Clock pin of the interface If no clock is detected it i...

Page 96: ...Clocking CDM 550T Satellite Modem 10 4 Rev 1 3 Figure 10 1 Tx Clock Modes...

Page 97: ...CDM 550T Satellite Modem Clocking Rev 1 3 10 5 Figure 10 2 RX Clock Modes...

Page 98: ...Clocking CDM 550T Satellite Modem 10 6 Rev 1 3 This page has been intentionally left blank...

Page 99: ...bits are the user s data This increases the rate of transmission by 5 approximately 1 6 for the Turbo BPSK cases For example if the user s data rate is 64 kbps the actual transmission rate will now b...

Page 100: ...frame permits the de scrambler to correctly recover the data The user s data is extracted and sent through additional processing in the normal manner The extracted overhead bytes are examined to deter...

Page 101: ...en sending a poll request and receiving a response will be around 5 seconds Note that when either of the BPSK Turbo rates are in use the overhead rate is reduced by a factor of three and therfore the...

Page 102: ...EDMAC Channel CDM 550T Satellite Modem 11 4 Rev 1 3 This page has been intentionally left blank...

Page 103: ...osed loop feedback system is created over the satellite link A particularly attractive benefit of this feature is that whenever framed operation is selected the remote demodulator s Eb No can be viewe...

Page 104: ...the user will be prompted to define four key parameters 12 2 1 Target Eb No This is value of Eb No that the user desires to keep constant at the remote modem If the Eb No exceeds this value the AUPC c...

Page 105: ...sation Rate As with any closed loop control system the loop parameters must be chosen to ensure stability at all times Several features have been incorporated to ensure that the AUPC system does overs...

Page 106: ...16 0 dB will be displayed As long as framing is enabled the value will still be available even though AUPC may be disabled Also displayed is the current value of TX power increase If Framing is enabl...

Page 107: ...dows 3 1x Windows 95 98 or Windows NT This utility program is called CCCFlash exe and should be copied to the user s computer hard disk Along with this the user will receive the latest firmware file f...

Page 108: ...Flash Upgrading CDM 550T Satellite Modem 13 2 Rev 1 3 This page is intentionally blank...

Page 109: ...ate 5 16 BPSK Turbo Operating modes Transparent Closed Network Proprietary EDMAC framed mode 5 overhead addition all modes except BPSK Turbo 1 5 overhead addition Rate 21 44 and 5 16 Turbo RS Outer Co...

Page 110: ...requency and temperature Output impedance 50 and 75 ohms front panel selectable 17 dB minimum return loss O P connector BNC female Clocking options Internal 1ppm External locking over a 100 ppm range...

Page 111: ...3 4 Guaranteed Eb No typical value in parentheses 5 9dB 5 5dB 6 5dB 6 0dB 7 0dB 6 5dB Rate 7 8 Guaranteed Eb No typical value in parentheses 7 2dB 6 6dB 7 7dB 7 2dB 8 3dB 7 7dB VITERBI and RS 220 200...

Page 112: ...rfaces Built in EIA 422 EIA 530 DCE also supports X 21 DCE and DTE V 35 DCE Synchronous EIA 232 Asynchronous EIA 232 maximum data rate 56 kbaud Front panel selectable Pinout Per EIA 530 25 pin D type...

Page 113: ...99 999 kbps up to 2400 baud 200 to 399 999 kbps up to 4800 baud 399 999 kbps up to 9600 baud Rate 1 2 BPSK modes are limited to 4800 at rates above 550 kbps Main channel data rate versus async channel...

Page 114: ...5 male Input Signal power in selected IF filter bandwidth 50 45 40 35 30 25 20 15 10 5 0 0 1 2 3 4 5 6 7 8 9 10 11 For Symbol Rates 300 ksym sec IF BW 3 5 MHz For Symbol Rates 33 ksym sec IF BW 110 kH...

Page 115: ...ter sections 15 2 EIA 485 For applications where multiple devices are to be monitored and controlled a full duplex or 4 wire EIA 485 is preferred Half duplex 2 wire EIA 485 is possible but is not pref...

Page 116: ...data is carried via EIA 232 electrical levels on one conductor and target to controller data is carried in the other direction on the other conductor 15 4 Basic Protocol Whether in EIA 232 or EIA 485...

Page 117: ...SCII code 13 10 2 characters Example 0654 RSW 32 CR LF Each of the components of the packet is now explained 15 5 1 Start Of Packet Controller to Target This is the character ASCII code 61 Target to C...

Page 118: ...arget is used as the assignment operator and is used to indicate that the parameter defined by the preceding byte should be set to the value of the argument s which follow it For example in a message...

Page 119: ...set a parameter to a particular value then if the value sent in the argument is valid BUT the modem will not permit that particular parameter to be changed at that time the target will acknowledge the...

Page 120: ...Remote Control CDM 550T Satellite Modem 15 6 Rev 1 3 This page has been intentionally left blank...

Page 121: ...bps between 2 4 kbps and 2048 kbps Resolution 1 bps Example TDR 2047 999 which is 2047 999 kbps TDR message ok TDR received ok but invalid arguments found TFQ message ok but not permitted in current m...

Page 122: ...st be set for Rate 21 44 or 5 16 Turbo mode 2 QPSK must be set for Rate 3 4 Turbo QPSK mode 3 OQPSK must be set for Rate 3 4 Turbo OQPSK mode All other codes invalid Example TMD 2 which is QPSK TMD me...

Page 123: ...mmand 1 On 2 Off due to ext H W Tx Carrier Off command not a valid argument when used as a command All other codes invalid Example TXO 1 which is Tx Carrier On TXO message ok TXO received ok but inval...

Page 124: ...to query the options fitted Values 5 8 may affect RCR or RMD RFT message ok RFT received ok but invalid argument found RFT message ok but not permitted in current mode RFT RFT x same format as command...

Page 125: ...argument Rx Demod Acq Sweep Width RSW 2 bytes numerical Command or Query Rx acquisition sweep range of demodulator in kHz ranging from 1 kHz to 30 kHz Example RSW 09 which is 9 kHz RSW message ok RSW...

Page 126: ...nd FRM message ok but not permitted in current mode FRM FRM x same format as command argument Unit Test Mode TST 1 byte value of 0 1 2 3 4 or 5 0 Normal 1 IF loopback 2 Digital loopback 3 I O loopback...

Page 127: ...rguments found ESA message ok but not permitted in current mode for example if ESA is sent to a distant end slave unit ESA ESA xxxx same format as command arguments Circuit ID string CID 24 bytes ASCI...

Page 128: ...remote demod d Maximum increase in Tx Power permitted in dB Example APP 015 67 APP message ok APP received ok but invalid arguments found APP message ok but not permitted in current mode APP APP abc...

Page 129: ...x Clock Source same as TCK 1 byte X Tx Carrier Status same as TXO 1 byte f Rx Frequency same as RFQ 8 bytes d Rx Data Rate same as RDR 8 bytes g Rx FEC Decoding type same as RFT 1 byte r Rx FEC Code R...

Page 130: ...9 Command only Forces the unit to retrieve the Configuration Memory location defined by the one byte argument 0 to 9 and to re program the unit with that stored configuration CLD message ok CLD messa...

Page 131: ...A N A Read EEPROM Value N A 3 bytes Query only FACTORY USE ONLY A query in the form aaa where aaa is a starting bit address in the range 0 127 within the modem s serial EEPROM requesting that the byt...

Page 132: ...75 bytes Query only Unit returns the oldest 5 Stored Events which have not yet been read over the remote control Reply format CR Sub body CR Sub body CR Sub body CR Sub body CR Sub body where Sub body...

Page 133: ...uments Retrieve Number of unread Stored Statistics N A 3 bytes numerical Query only Unit returns the number of Stored Statistics which remain unread in the form xxx Note This means unread over the rem...

Page 134: ...codes for an argument Example LRS 1 unit is in remote mode LRS message ok LRS LRS x see description for details of arguments Serial Number SNO 4 bytes numerical 0000 to 9999 Command portion is FACTORY...

Page 135: ...rdware Tx Traffic and Rx Traffic in the form abcde where a Unit fault status b Tx Traffic status c Rx Traffic Status d Change in Fault Status since last poll 0 none 1 change e Change in Unit Configura...

Page 136: ...Remote Control CDM 550T Satellite Modem 15 22 Rev 1 3 This page has been intentionally left blank...

Page 137: ...especially for existing EIA 422 449 and V 35 users a conversion must be made For these situations the following two cable drawings show EIA 530 to EIA 422 449 DCE conversion and EIA 530 to V 35 DCE co...

Page 138: ...Cable Drawings CDM 550T Satellite Modem A 2 Rev 1 3...

Page 139: ...CDM 550T Satellite Modem Cable Drawings Rev 1 3 A 3...

Page 140: ...Cable Drawings CDM 550T Satellite Modem A 4 Rev 1 3...

Page 141: ...ndix B Eb No MEASUREMENT Although the CDM 550T calculates and displays the value of receive Eb No on the front panel of the unit it is sometimes useful to measure the value using a spectrum analyzer i...

Page 142: ...the noise density To make this measurement use a vertical scale of 1 or 2 dB division and use video filtering and or video averaging to reduce the variance in the displayed sweep to a low enough leve...

Page 143: ...1 2 3 1 6 6 0 4 7 7 7 1 7 4 7 2 9 2 2 6 5 5 4 8 4 2 4 5 4 3 6 2 9 7 0 6 0 9 0 3 0 6 0 4 2 3 5 7 5 6 6 9 6 3 6 6 6 4 8 4 1 8 0 7 3 10 3 4 3 7 3 5 5 4 8 8 5 7 8 10 8 4 8 7 8 6 0 5 3 9 0 8 4 11 4 5 4 8...

Page 144: ...Eb No Measurement CDM 550T Satellite Modem B 4 Rev 1 3 This page is intentionally left blank...

Page 145: ...rame format that EDMAC uses and continues to add 5 to the transmitted bit rate In order to provide external access without using the main Remote Control connector on the rear panel the Auxiliary Seria...

Page 146: ...t hand side Rx D Gnd Tx D Input Output Pin 1 Baud Rates The main channel data rate versus async channel baud rate is as follows All modes except 21 44 and 5 16 Turbo 50 kbps option disabled 50 to 99 9...

Page 147: ...a special combination of keystrokes for FACTORY access which we do not publish Therefore if a customer wishes to select this mode Customer Service should be contacted who will then provide instruction...

Page 148: ...Async Overhead Option CDM 550T Satellite Modem C 4 Rev 1 3 This page is intentionally left blank...

Page 149: ...Cables 2 2 Connector Pinouts 5 1 Conventions and References viii Customer Support ii D Data Connector 25 Pin D Type Female 5 1 Data Connector 25 Pin D Type Female 5 1 Data Interfaces 1 3 Data Interfa...

Page 150: ...5 1 Remote control 15 1 Reporting Comments or Suggestions Concerning this Manual ix RF Loopback 6 28 RX Clock Modes 10 5 S Safety Notices ix Select Internal IF Loop 2 2 Select 6 4 Sequential Decoding...

Page 151: ...CDM 550T Satellite Modem Monitor and Control of the KST 2000A Satellite Terminal Addendum A For Modem Firmware V1 20 or higher Part MN CDM550T AA1...

Page 152: ...ranteed or warranted and they are not intended to be nor should they be understood to be representations or warranties concerning the products described Further Comtech EF Data reserves the right to m...

Page 153: ...on 4 ODU ENABLE CONFIG TRANSMITTER 4 ODU ENABLE CONFIG TRANSMITTER FREQUENCY 4 ODU ENABLE CONFIG TRANSMITTER ATTEN Attenuation 5 ODU ENABLE CONFIG TRANSMITTER OUTPUT 5 ODU ENABLE CONFIG TRANSMITTER HP...

Page 154: ...C 7 ODU ENABLE CONFIG MISCELLANEOUS 8 ODU ENABLE CONFIG MISCELLANEOUS AGC AUTO GAIN CONTROL 8 ODU ENABLE CONFIG MISCELLANEOUS REF ADJUST 8 ODU ENABLE INFO Information 8 ODU ENABLE INFO TRANSMITTER 9 O...

Page 155: ...ion of Comtech EF Data s KST 2000A Satellite Terminal from the front panel using the keypad and display of a CDM 550T modem Nested menus display all available options and prompt the user for required...

Page 156: ...appropriate If this is a numeric field this will decrement the value Enter ENT Used to accept an edited entry Most menus prompt the user to press this key by displaying the text PRESS ENTER ENTER or...

Page 157: ...user to monitor the alarm status of the modem to view the log of stored events and to display the Receive Parameters screen STORE LD Store Load This menu branch permits the user to store and to retrie...

Page 158: ...r Misc configuration branch Use the keys then press ENTER 1 2 5 ODU ENABLE CONFIG TRANSMITTER ODU TX FREQUENCY ATTEN OUTPUT HPA ENTER This menu item is used to select which ODU Transmitter parameter i...

Page 159: ...SELECT KST TX OUTPUT OFF ON WARM ENTER The user is prompted to select either ON OFF or WARM using the keys then press ENTER WARM is OFF if COLD WARM is ON if warm and NO FAULTS FAULTS present stays W...

Page 160: ...s used to select which ODU Receiver parameter is to be modified Use the keys then press ENTER 1 2 13 ODU ENABLE CONFIG RECEIVER FREQUENCY EDIT ODU RX FREQUENCY 10950 0 MHz PRESS ENT The user is prompt...

Page 161: ...STATE SELECT ODU LNA STATE ON OFF PRESS ENTER The user is prompted to select either ON or OFF using the keys then to press ENTER This controls whether or not the ODU will provide LNA POWER via the Rec...

Page 162: ...he keys then to press ENTER 1 2 21 ODU ENABLE CONFIG MISCELLANEOUS REF ADJUST EDIT INT REF ADJUSTMENT 028 PRESS ENTER The user is prompted to edit the INT 10MHz REF setting using the keys then to pres...

Page 163: ...2000A Receiver information including Rx Frequency and Rx Attenuation press ENTER 1 2 25 ODU ENABLE INFO HPA HPA ON FAULT LOGIC NO SUMMARY 1 2 26 ODU ENABLE INFO LNA LNA ON FAULT LOGIC NO SUMMARY This...

Page 164: ...of 6 detailed status windows Use the keys then press ENTER The cursor may be moved over 6 of the 7 status parameters to view more detailed status information These screens are continually updated whi...

Page 165: ...CDM 550T Satellite Modem Monitor and Control of the KST 2000A Satellite Terminal Addendum A For Modem Firmware V1 20 or higher Part MN CDM550T AA1...

Page 166: ...ranteed or warranted and they are not intended to be nor should they be understood to be representations or warranties concerning the products described Further Comtech EF Data reserves the right to m...

Page 167: ...on 4 ODU ENABLE CONFIG TRANSMITTER 4 ODU ENABLE CONFIG TRANSMITTER FREQUENCY 4 ODU ENABLE CONFIG TRANSMITTER ATTEN Attenuation 5 ODU ENABLE CONFIG TRANSMITTER OUTPUT 5 ODU ENABLE CONFIG TRANSMITTER HP...

Page 168: ...C 7 ODU ENABLE CONFIG MISCELLANEOUS 8 ODU ENABLE CONFIG MISCELLANEOUS AGC AUTO GAIN CONTROL 8 ODU ENABLE CONFIG MISCELLANEOUS REF ADJUST 8 ODU ENABLE INFO Information 8 ODU ENABLE INFO TRANSMITTER 9 O...

Page 169: ...ion of Comtech EF Data s KST 2000A Satellite Terminal from the front panel using the keypad and display of a CDM 550T modem Nested menus display all available options and prompt the user for required...

Page 170: ...appropriate If this is a numeric field this will decrement the value Enter ENT Used to accept an edited entry Most menus prompt the user to press this key by displaying the text PRESS ENTER ENTER or...

Page 171: ...user to monitor the alarm status of the modem to view the log of stored events and to display the Receive Parameters screen STORE LD Store Load This menu branch permits the user to store and to retrie...

Page 172: ...r Misc configuration branch Use the keys then press ENTER 1 2 5 ODU ENABLE CONFIG TRANSMITTER ODU TX FREQUENCY ATTEN OUTPUT HPA ENTER This menu item is used to select which ODU Transmitter parameter i...

Page 173: ...SELECT KST TX OUTPUT OFF ON WARM ENTER The user is prompted to select either ON OFF or WARM using the keys then press ENTER WARM is OFF if COLD WARM is ON if warm and NO FAULTS FAULTS present stays W...

Page 174: ...s used to select which ODU Receiver parameter is to be modified Use the keys then press ENTER 1 2 13 ODU ENABLE CONFIG RECEIVER FREQUENCY EDIT ODU RX FREQUENCY 10950 0 MHz PRESS ENT The user is prompt...

Page 175: ...STATE SELECT ODU LNA STATE ON OFF PRESS ENTER The user is prompted to select either ON or OFF using the keys then to press ENTER This controls whether or not the ODU will provide LNA POWER via the Rec...

Page 176: ...he keys then to press ENTER 1 2 21 ODU ENABLE CONFIG MISCELLANEOUS REF ADJUST EDIT INT REF ADJUSTMENT 028 PRESS ENTER The user is prompted to edit the INT 10MHz REF setting using the keys then to pres...

Page 177: ...2000A Receiver information including Rx Frequency and Rx Attenuation press ENTER 1 2 25 ODU ENABLE INFO HPA HPA ON FAULT LOGIC NO SUMMARY 1 2 26 ODU ENABLE INFO LNA LNA ON FAULT LOGIC NO SUMMARY This...

Page 178: ...of 6 detailed status windows Use the keys then press ENTER The cursor may be moved over 6 of the 7 status parameters to view more detailed status information These screens are continually updated whi...

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