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T1 circuit or device help

  1. Apr 17, 2012 #1
    I work in the electronics industry on radio communications specifically. The radios I maintain are not usually located at the facility in which they are used. Meaning the tramsmitters and receivers are located several miles from their respective operators, and the audio signals as well as the push-to-talk signalling are transmitted back and forth (from the operators to the tramsmitter/receiver facility) via a T1 line. A busy signal, or "high" on the T1 line is what we use to key the transmitters.
    The problem i am experiencing is when we have a T1 problem, or the local telephone company needs to do checks on the line, they run what is known as a "Stress Test" which is a properly "framed" T1 signal with all "highs". This is meant to stess the line to its max potential and the phone technicians use this data to evaluate the line.
    As you can see the problem is when they run this test, it will key all the radios in the facility. This is mainly an issue when the testing is done without the radio technician's knowledge, or someone is unaware that this will happen.
    I am in need of a circuit or device that will accept a T1 input (from a RJ-45 connector) and pass all valid inputs EXCEPT the properly framed T1 with all "highs", there is never a scenario in which we would want all the radios keyed at once.

    Thanks in advance for your help
  2. jcsd
  3. Apr 20, 2012 #2
    What is radio keying?

    So you need a filter that takes an RJ-45 copper input and outputs the same? That filter needs to filter out only properly framed T1 with all highs?

    Can you provide some more information about this T1 "high" signal?
  4. Apr 20, 2012 #3
    I would think the solution to your problem would be at your T1 mux that interfaces to your radio transmitter. I beleive that where I work we have a simular set up and key in the same way. When we get an all ones condition though, the mux goes into an alarm, but does not assert an "E" keying lead. Maybe you should look at your mux documentation as there might be a setting for how it handles an "all ones" condition.
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