Spectra with SIU and HHCH display issue on some channels

[Jim202]

I have a problem with the HHCH not showing the normal 2 digit
channel display on some of the channels. It shows one digit
and one letter on about 9 of the 90 channels programmed
into the radio.

The radio is originally one of the government dual radio
(VHF and UHF) packages. They came with the DES boxes
between the radios and the SIU (Serial Interface Units) and
a siren package. Both the siren and the DES boxes have
been removed and taken out of the programming. The
VHF radio works just fine on all of the 90 channels.

The problem follows the SIU box. If I put a different SIU
on the radio, the problem isn't there.

My feeling is that there is a programming issue with the
SIU box. Does anyone know how to resolve this problem
so that all the channels will show up as normal 2 digits
on the HHCH?

I have a number of these Spectra radios that I have
done the same mods to and never ran into this channel
display problem.

Jim

[Mike B]

The SIU has its own microprocessor. The microprocessor talks Systems 9000 asynchronous serial data to the radio drawer and a special synchronous serial data to the HHCH. If you are seeing any HHCH display at all or able to change modes etc., I would think the HHCH synchronous serial data bus is working. The SIU has its own special version of a MLM board (not interchangeable with a Spectra MLM).

The Syntor X had a special HHCH display option that would emulate the A, B, C and D buttons on the old push button control heads. It would display a number (1 to 8 ) and a letter (A to D). If the display you are seeing matches this type of format then your SIU is using a display that mimics an old up to 4 bank 32 pushbutton head display. There was even a special purpose Syntor X HHCH (it does not use the Spectra synchronous serial data connection, so its not compatible) that used a single 14 segment and a single 7 segment LED on the HHCH display so it could do a better job of displaying a letter with the 14 segment LED.

The hard part is I cannot tell you if a letter/number display is caused by special SIU MLM firmware, RSS programming or SIU jumper settings. Try reading a code plug from a working SIU radio setup, swap the SIU you are having trouble with onto that radio and programming the same code plug back into it. If its a RSS issue it would make sense that writing a good code plug into the problem SIU would take care of it. If the code plug write works, but it does not fix your problem it could be the SIU MLM firmware, SIU jumpers or a broken SIU.

[mancow]

It's an option in the SIU programming software.

You can make the channels display anything as long as it's in HEX. A simple re-write of the SIU will fix it.

[Jim202]

Can you explain how you re-write the SIU to fix this.

Jim

It's an option in the SIU programming software.

You can make the channels display anything as long as it's in HEX. A simple re-write of the SIU will fix it.

[mancow]

You use the SIU ultra ancient RSS that is basically a SYNTOR X9000 type program. It won't run on anything much over an abacus but it's about as simple as it gets when it works.

There should be a table for each side Vhf / Uhf. You tell it how many channels each side has and what should be displayed.

That's it. Of course, the radio channel programming must mach what's in the SIU too.

[Jim202]

If it isn't asking too much, what's the chance of passing along the Motorola part number of this ancient RSS.

You seem to be able to get around it and talk like you have solved this problem before.

Jim

You use the SIU ultra ancient RSS that is basically a SYNTOR X9000 type program. It won't run on anything much over an abacus but it's about as simple as it gets when it works.

There should be a table for each side Vhf / Uhf. You tell it how many channels each side has and what should be displayed.

That's it. Of course, the radio channel programming must mach what's in the SIU too.