Hardware Support

Your question may be answered on the FAQ page

A Capability Upgrade for AS/KU-8xx and AS/KL 9000 FPDA Data Terminals is now available.


All KU-891G units running firmware previous to version 1.7 must be upgraded to the latest version. You can tell which firmware version your unit is running by turning the terminal on and then performing a self-test. There has been considerable changes made in v1.7 in order to make the unit's GPS messaging system compatible with other equipment such as the KU-894. All GPS-related messages in firmware previous to v1.7 are not compatible with v1.7 onwards. The bug in the unit's GPS fix request routine has also been fixed along with several other minor bug fixes and improvements. Please contact your supplier to arrange a firmware upgrade to the latest version, or contact:


If your CYCOM product cannot obtain a GPS fix it may be that the internal GPS has reset itself to default mode.

To workaround this problem:

Run your Cycom software (ASKL 918, KU893 etc.) at least once to force the GPS into NMEA mode, making sure that the GPS is enabled in the software. Then shut the Cycom software down.

Click the 'Start' button.

Select 'Run'.

Type 'hypertrm' (without quotes) in the 'Open' box and hit 'OK'.

If asked for location information just enter any number in the area code and hit 'Close'.

If asked to install a modem hit 'No'.

When asked to pick a name and icon for the connection just type 'test' for the name and hit 'OK'.

In the 'Connect to' dialog box make sure 'COM3' is selected in 'Connect using' and hit 'OK'.

In the COM3 'properties' dialog make sure:
'Bits per second'=4800
'Data bits'=8
'Stop bits'=1
'Flow control'=Hardware
Then hit 'OK'

In the HyperTerminal window goto 'File' then 'Properties'.

On the 'Settings' tab goto 'ASCII Setup'.

Make sure 'Send line ends with line feeds' is ticked.

Make sure 'Echo typed characters locally' is ticked.

Hit 'OK' to close the 'ASCII setup' window, and 'OK' to close the 'Properties' window.

Type, in uppercase, in the text area of the HyperTerminal window:
and hit 'Enter'.

You should see the screen start to fill with reports from the GPS (each line starting with '$GPGGA'), so you won't be able to see what you next type, however, if successful you'll see additional responses coming from the GPS like '$GPGSA' or 'GPRMC' etc. Type in the following, followed by 'Enter' for each line:

These are the only commands needed for Cycom software, however you may have other software which uses other commands, so you may need to additionally type in the following:

Close HyperTerminal, hitting 'Yes' if asked to disconnect, and 'No' to saving the session.

The Cycom software should now be able to get a fix from the GPS.

This has been identified as a problem with AS/KL-918 Combat Data Terminals but may affect other CYCOM equipment fitted with internal GPS. This issue has been resolved in V1.1 of the AS/KL 918 software. To organise an upgrade contact:


Users of CYCOM® products will notice that for many years cables associated with our equipment were identified by thirteen digit numbers which were similar in appearnce to NSNs.

Over time, many cables in our product range did in fact obtain correctly specified NSNs and from 01.01.03 to prevent confusion over numbering CRL will drop the first 6 numbers of any 'in house' part number. For example, a previously designated CRL 5875-00-900-0003 cable will now become a 900-0003 cable.

Correctly listed NSN cables will retain their numbers but their 'in house' CRL designator number will still revert to a seven digits.

For assistance regarding this change, in the first instance contact or fax or phone support at our normal numbers.

AS/KL-915 COMBAT DATA TERMINAL (NSN 5810-66-141-5668)

Rougher than normal handling and incorrect packaging during shipment has resulted in damage to, or failure of, the battery retaining thumb-screws on this equipment. Investigation indicates that the use of brass for these items also contributes to the problem.

CRL has available - and now fits as standard - improved thumb-screws made from black anodized stainless steel. These new items are a direct replacement.

Those users who have not contacted us about replacement screws for in service equipment should contact us at:


All users of AS/KL CYCOM(tm) products should take steps to ensure that their radio and radio/printer leads are terminated in accordance with CRL drawing ASKL-916-008e.

Recent cable inspections by CRL indicated that in cases where radio connectors were installed "after market" those carrying out this task did not follow our wiring diagram. As a result performance of the associated equipment was degraded.

The neccessary drawing is available to users either by secure fax or by mail. In the first instance contact or fax or phone at our normal numbers.


All users of CYCOM(tm) IF-921 TEMPEST fibre optic modems should be aware of the fact that a number of variants exist which can only be identified by by the serial number. Three serial number sequences exist

92199016 - a normal IF-921
921H99016 - a high speed (250Kb) IF-921
921HS99016 - a high speed (250Kb) special protocol (reduced delay) IF-921

Because of the protocol changed with the HS modems, THEY WILL NOT WORK with other IF-921 units. HS units must be used as a pair at all times.

Users of IF-921 products who do not have test facilities for F/O modems can purchase from us a self contained TS-921 modem test set. This unit supplies modem power and can test all 16 channels (while recording errors) in either a loop back or link mode.

If you require futher assistance with our fibre optic modem products first instance contact or fax or phone at our normal numbers.


All users of CYCOM™ data terminals should be aware of the audio level requirements for connection of our data terminals to radio equipment. Operation outside these prescribed levels will result in poor performance due to weak/distorted signals resulting in corrupted messages.

KY-900A Secure voice adapter - Aircraft variant

Audio side mic in 1.0V – 5V RMS, headphone out 2.0V- 8.0V RMSRadio side Rx in 2.0V – 8V RMS, Tx out 1.0V – 5V RMS

KU-893A combat data terminal – Aircraft variant

Transmit 0dbm into 600 ohmsReceive 200mV – 2V RMS

KY-900N Secure voice adapter and KU-893 combat data terminal – Naval variant

Transmit 0dbm into 600 ohmsReceive 200mV – 2V RMS

All remaining combat data terminals KU-xxx & AS/KL-xxx and Secure voice equipment KY-xxx

Transmit 50mV RMSReceive 200mV – 2V RMSD10 Output 600mV unloaded, 300mV loadedD10 Input 100mV – 2V RMS

While it is often obvious to users that they have low transmit audio ( the actual transmitted signal sounds weak) it is not so obvious with low receive audio. If users are unable to actually measure receive audio levels we suggest that the self test function be used as an ‘ad hoc’ millivolt meter to determine if the correct receive level is present. To do this first carry out a self test with radio equipment disconnected (as detailed in the instruction card) to check the unit is ok. With the unit connected to an active receiver carry out another self test and observe the results. If a ‘modem fail’ appears then the incoming audio was sufficient to swamp the internal test signal and is therefore about the right level. If the modem does not fail then the incoming receive signal is low and it should be increased until failure occurs. This ‘old jungle trick’ IS NOT a substitute for a correctly engineered interface.

Users of RAVEN equipment should not be fooled by extension speaker volume, as this does not reflect the level supplied to a handset connected CYCOM™ terminal. Irrespective of speaker volume the HANDSET volume should be at ¾ turns, or sufficient to introduce a ‘modem fail’ during self test.

If you require further assistance with our secure communications products in the first instance contact or fax or phone support at our normal numbers