GM300 to C100 remote

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Jtsou
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GM300 to C100 remote

Post by Jtsou »

Can someone lead me in the direction of using an Old GM300 connected to C100 remotes to provide radio audio throughout a station?

Our new radio system is digital so the old analog infrastructure is no longer used.

Our station has 3 C100 remotes in different rooms that are now lying dormant. It was previously connected to a CDM1250 and could be used to transmit/receive on the paging channel. There was a tone remote module that was connected. The cdm1250 and the tone remote have now been sold.

My question is can a GM300 be connected to the tone remotes to receive paging(analog) audio in the station without the tone remote?

Thanks for the help.
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kb4mdz
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What radios do you own?: Too many for the time I have.

Re: GM300 to C100 remote

Post by kb4mdz »

I'll restart typing since I started without fully reading. Dummy me. :-D

Yes, you can, but you'll basically need the 'tone remote module' aka tone remote adapter, like a CPI TTP-1 or MR2

http://www.cpicomm.com/ttplitwpics.pdf00; it says that the correct cable is supplied with the MR200.

Look on your favorite auction site, eh?

You could probably cobble something together if you just want receive audio, but still the easier way to to us a remote adapter.
Jtsou
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Re: GM300 to C100 remote

Post by Jtsou »

How would I put this together for receive only? Since the radio would not be used for transmitting anyway. Thanks
RFguy
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Re: GM300 to C100 remote

Post by RFguy »

Do you only want to receive on the C100's?

If so, just connect the GM300 RX audio to the C100 control lines. should work, but may need an isolation transformer and maybe a DC blocking cap.

(just noticed kb4mdz also mentioned about RX only before me)
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kb4mdz
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Re: GM300 to C100 remote

Post by kb4mdz »

If you just want to do RX audio, you can do a couple different things:

1) Take your RX audio off the speaker leads, accessory connector 1 & 16; this will be after the Volume control, and certainly no impedance matching between the speaker output circuit and the (theoretically ) 600 ohm impedance of the phone lines;

Or 2) Take your audio off from pin 11 (I think; RX audio, usually just after the discriminator, and maybe gated by PL tone, depending on the Audio Board's jumpers) & pin 7, ground; this is fixed level, from before the Volume control, and you'll be driving balanced phone lines with unbalabnced circuit, and again, no impedance matching,

or 3) Take either of the pin pairs above and pass them thru an RDL Labs TX-1A, set up as a matching transformer; better impedance match, you have some level control, etc.
Jtsou
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Re: GM300 to C100 remote

Post by Jtsou »

do you have a pin out for he C100s that I connect the GM300 audio to? Sorry for the ignorance. I looked for it however I was unable to find one.
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SteveC0625
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Re: GM300 to C100 remote

Post by SteveC0625 »

Jtsou wrote:do you have a pin out for he C100s that I connect the GM300 audio to? Sorry for the ignorance. I looked for it however I was unable to find one.
These threads might give you some more info for searching:

http://batboard.batlabs.com/viewtopic.php?t=70673
http://batboard.batlabs.com/viewtopic.php?t=56162
http://batboard.batlabs.com/viewtopic.php?t=87128
http://batboard.batlabs.com/viewtopic.php?t=111124

I would note that if you previously had the C100's hooked up to a CDM1250, the pinouts for the GM300 are nearly the same. If you still have the cabling and 16 pin accessory connector, you may be able to figure out what you need to do.
Jtsou
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Re: GM300 to C100 remote

Post by Jtsou »

I have found the tone remote. I have connected the remote back to the existing C100s at the station. I have looked and looked but have not found a cable to connect the two.

If i fashion my own cable, I just need to connect the following pins on the GM300 to the Tone panel correct? Channel steering is not necessary.

Code: Select all

GM300 -- L1548

7(GND) -- 1(RX aud -)
11(RX Aud) -- (RX Aud +)
3(Mic PTT) -- 6(PTT)
2(Mic Aud) -- 7(Mic hi)
14(PROG I/O?) -- 8(Monitor)<<<< not sure on this one
7(GND) -- 14(GND)
13(SWA+/sense) -- 13(DC+)

also, if I were to wire it correctly would the L1548 tone remote be capable of interfacing with a Harris CS7000 control station?

If i have it correct, I would connect the following...

Code: Select all

CS7000 -- L1548

1(EXT MIC HI 1) -- 7(MIC HI)
5(SWA+) -- 13(DC+)
7(GND) -- 12(GND)
10(FIXED LOW AUD OUT 1) -- 3(RX AUD +)
14(EXT MIC LOW 1) -- 9(MIC LO)
16(EXT MIC PTT) -- 6(PTT)
23(LOW LEV AUD OUT) -- 1(RX AUD -)
Sorry for the questions. But I am trying to figure out the best way to go about this while staying on a volunteer dept budget.

Thanks
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