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The files: s990files.zip

These should give you the information needed to convert your S990 control unit for front panel entry of frequency and CG tone data. Be sure and read both text files included.

A few images:

The first one shows what you will get when you power up the unit with the 'ADD' and 'DELETE' buttons pressed. This lets you select in which MODE to change data. The MODE up and down buttons are used:




Once the MODE is selected, you will step on to the CHANNEL window to select which channel you will modify. The CHANNEL up and down buttons are used:




The next step gets you to the transmit frequency (the tx light is on) where you use the MODE, CHANNEL and SCAN keys to change the data:




The next step is for the transmit CG tone that is entered from the table. "00" is no tone:




The next step will be for the receive frequency (the busy light is on) and again you will use the MODE, CHANNEL and SCAN keys to change the data:




The next step is for the receive CG tone that is entered from the table. "00" is no tone (carrier squelch):




Once all the changes are made, the unit is reset and returns to normal operation. From what I can tell, none of the normal functions of the control unit are affected, such as its excellent dual priority scan.




To make the frequency changes write to the head's internal eeprom, a programming jumper must be in place. This jumper goes between pins 3 and 4 on the rear of the unit where the GE 'suitcase' programmer would normally connect. In my case, I found it worked out well to add a small switch in the head between these pins:




This made it much easier to change a channel frequency 'on the fly'




The end results is that I have a very handy-dandy mobile unit:




Good luck on your project!

David - WD4JKH


Last changed on 7/17/2003