Motorola CDM 2 Tone Sequential

[JD]

I have an application where the customer needs to page out on their CDM 1250 VHF base 2 different sets of paging tones, (not at the same time).They do not want to use the CDM buttons to set off the tones. I am planning on the following set up so only one button will need to be used and keep it simple for the operator.

I will use 2 Comm Specialists 2 tone sequential encoding boards and place momentary push buttons on the cabinet.

Should I feed the tone output into the CDM accessory pin number 2, Mic Hi, or the flat trmasmit audio pin on the accessory connector ? The accessory connector is also being used to connect to a UHF link radio,( Mic Hi PIn only).

Thanks.

[Al]

I've done the same thing with commercial series CM300s and used the flat tx audio pin on the accy connectors. The only difference between the two, disregarding tone level requirements, is that the mic input is preemphasized at 6 dB/octave and the flat tx obvoiusly is not. So if you use the mic input, you stand the chance of more distortion on the higher frequency tones. If you use the flat tx input, deviation on both tones should be approximately the same.

[JD]

Thanks for the feed quick response , I will use the Flat Transmit Audio pin.

[wavetar]

There is also filtering on the mic input which causes lower frequency tones to be attenuated, especially below 350Hz. Always best to use the flat tx input for paging.

[JD]

Thanks for the reply, very helpful. I will start using Flat XMIT pin for tones.

[JD]

I tried using the Flat Audio Pin , No tones are passing. I posted another thread on how this is configured, it is a cross band bi directional uhf to vhf repeater. If I configure the VHF radio to pass the tones, then the PL on the vhf when repeater is used, goes astry, 2200 hx, all over the place. I have configured the set up on both radios and can not get tones and valid PL to work.

It will work fine if I pass the ST 804 tones on the MIC high pin #2 on the vhf radio.

[jackhackett]

I see that there are 2 "external call button" settings for the accessory pins, is it possible to set up the tones in the radio and send them with buttons connected to these pins? I couldn't find a good description of this function anywhere.

[JD]

That is waht I usually do, however this customer only wants to push a button to set off tones, he does not want to have to select using buttons on the radio.

[Jim202]

One word of caution to the wise radio tech, make sure the deviation of the tones is not into compression.
It is a very common mistake for the radio tech to set the paging tones at the same deviation as the
normal voice is set to. You never want to set paging tones this high. this is even more important
if you are using the radio as a control station working through a repeater.

Most of the older radio geeks like myself, will advise you to set the paging tones to no more than
+/- 3.5 KHz. on a normal wide band channel. If your using the radio to go through a repeater,
most radio techs have a bad habit of setting the repeater audio throughput to have 3 KHz in and
4.5 KHz out. This will jam the audio right into compression and distort any paging tones being
sent.

I will stop here and say no more. This topic has been gone over many times on many chat groups.

Jim

Thanks for the feed quick response , I will use the Flat Transmit Audio pin.

[JD]

Thanks, I am setting them on the out put at 4.0 Khz. with a PL tone included. Will this work?

[JD]

I have got the repeater set up and 2 tones seq. is working. Had to make changes in the Audio Type, Filtered did not work .

The customer wants it so that when the desk mic is used, only one, they want both UHF and VHF to transmit. I have wire the mic into the accessry connector and have also tried a dulex adapter in the mic connectors using only one mic.

When I key the mic , the repeater locks.