Phone/radio interconnect control

[Jim]

Thanks for reading and apologies for being so vague.

I have a phone/radio interconnect that relies on the phone user switching
the rx and tx by using the dtmf tones on a handset (* and # from memory).
Just wondering if I can supply the tones to the interconnect as the phone
user or radio user talks.
Any ideas of how I might go about this gratefully accepted.

Cheers
Jim

 

[Alan]

On Sat, 11 Sep 2004 14:00:35 +1000, "Jim"
<jimshire1_nospam@nospam_iprimus.com.au> wrote:

Thanks for reading and apologies for being so vague.

I have a phone/radio interconnect that relies on the phone user switching
the rx and tx by using the dtmf tones on a handset (* and # from memory).
Just wondering if I can supply the tones to the interconnect as the phone
user or radio user talks.
Any ideas of how I might go about this gratefully accepted.

Cheers
Jim

You don't say whether it is for VHF/UHF or HF use.

Commonly on VHF/UHF the switching is controlled by the RX squelch
line. When the mobile talks it cuts off the speech from the line.

The TARA and the TACT both use the squelch line.

On HF it is normally the voice on the telephone line which operates a
VOX type switching arrangement, but you have to be careful that the
VOX isn't operated by the received audio from the RX.

The Codan/IPC 500 telephone interconnect uses a hybrid transformer
which is balanced to the line conditions at the beginning of the call.

The Barrett 660/960 telephone interconnect uses a hands free telephone
type IC to split the telephone line into TX and RX components.

The above is very basic but might give you some ideas.

HTH
Alan

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Web Site: http://www.jenal.com
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