GAI-Tronics MRTI 2000 (No. PL1877A) Microprocessor Radio Telephone Interconnect Installation & Service Manual - Manual (Page 69)

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Operator Instructions
Mobile Originated Calls
The PL1877A Radio Telephone Interconnect is capable of operating in three different modes to work
with different types of radio systems. Each of these types of systems requires a slightly different set of
mobile operating instructions. Therefore, it is important to refer to the section that applies to your
system.
Signal Search Simplex Mode
In this mode, the patch is installed at your base station. To access the telephone line (connect), push the
* button on your encoder. In about two seconds you should hear the dial tone, interrupted by short bursts
of squelch noise. These short bursts are sample intervals during which the patch is searching for your
transmitter signal and are heard only by the mobile radio users. When dial tone is heard, you may enter
the telephone number, “stretching” the duration of the first digit for about a second to enable the patch to
detect your transmitter signal.
You should follow the telephone number with another *. This second * tells the patch that you are
finished with telephone line signaling. If you omit this, the patch assumes you are finished 1 to 10
(programmable) seconds after the last digit has been entered and then opens the voice path to the
telephone line.
When the called party answers, you may converse in the same manner as with the base station operator.
You may interrupt the telephone party, but they cannot interrupt you and be heard. Each time you push
your microphone button, you should pause for about a half second before you begin speaking in order to
allow the patch to detect your transmitter signal. This eliminates lost words to the telephone line party.
When you release your microphone button, the telephone party hears a short beep to indicate that they
may speak and be heard by you. At the end of the conversation, push the
# button on your encoder,
stretching the duration for about a second. This disconnects the telephone line, and the patch confirms
disconnect back to you with a series of short beeps.
Optional control signaling should be handled in the same manner to the signal search mode by always
stretching the first control digit in order to be recognized by the phone patch. Many hand-held portable
radios are equipped with Touch-Code encoders that only put out a short burst of Touch-Code signaling.
The patch recognizes these units with no problem if the transmit button is pressed a second before the
Touch-Code signaling commences. Then, signaling may be entered at a normal rate.
Enhanced VOX Simplex Mode
In this mode, the patch is installed either on your base station, or on a wire-line remote control located
away from the radio base station. The feature unique to this mode of operation is the cross lock-out
between you, the mobile radio party, and the telephone line party. This means that whoever begins
speaking first maintains control of the conversation until they are finished speaking.
For example, after the first party finishes speaking, the second party may speak and maintain control of
the conversation until they are finished speaking. Then, the first party may speak and maintain control,
“locking out” the second party from being heard until speaking is finished. The patch recognizes
signaling tones to be different from speech and interrupts such tones as dial tone, busy tone, etc., for
mobile control. Typical operation is as follows: