
3oduction
AD913
Simplex Transceiver
(Walkie-Talkie)
Interface
In the following paragraphs we have used the word “transceiver” to refer to what are commonly called
walkie-talkies. The word “circuit” refers to two or more wired intercom stations which are connected, by cable, in
parallel, in a common-talk relationship. More than one independent communications circuit can exist in a Pro In-
tercom system. We will reserve the word “channel” to refer to a radio frequency shared by multiple transceivers.
The AD913 is NOT a transceiver. You must dedicate one of your transceivers to be connected to the AD913. The
combination then becomes your base.
The AD913 is an active device which allows communication between a Pro Intercom (or compatible) cabled system and
a simplex (press-to-talk/ release-to-listen) radio system, typically a pair or more of portable transceivers. To connect a full
duplex (simultaneous talk/listen) radio system, use the AD903.
The AD913 allows audio on the cabled communication system to be transmitted to one or more remote transceivers on
the same channel as the transceiver dedicated to be ‘base’, and transmissions from the remote units to be heard by par-
ties on the cabled circuit.
The AD913 connects directly to the transceiver dedicated to be “base’ via its auxiliary input/output connector (typically the
connector used for a remote mic/spkr accessory), converting it to a wireless base station on the cabled system. The
AD913 is powered from the intercom system’s power supply. The transceiver must have its own power source, either bat-
teries or an AC/DC power supply.
The AD913 provides a mic. level output for connection to the transmitter section of the transceiver, and has a line level in-
put to accept the headset level output from the receiver section of the transceiver. It also has a relay circuit to provide
push-to-talk (transmit-on) switching. (commonly referred to as PTT.)
The PTT function of the base transceiver is activated by pressing and holding the signal light button of any station on the
cabled circuit to which the AD913 is connected. The signal lamps on all other outstations will light, in the normal way. The
speech on the cabled circuit will be sent to the transmitter, and sent out to remote transceivers on the same channel. All
stations will know, by their signal lamp, that the transmitter is on. When the signal lamp button is released, incoming trans-
missions from the remote transceiver(s) are heard on the cabled circuit just as from another cabled station.
Setting up
The AD913 is intended for operation with a wide variety of transceivers - handheld, mobile or fixed types, and can be used
in many applications. It is therefore not possible to give definite instructions for setting up. However the following notes of-
fer a guide to avoiding most difficulties that might be experienced. By experimenting with layout, the optimal arrangement
will soon be found.
1. Connections between the AD913 and the transceiver are via the 6-pin XLR on the rear of the AD913. Pins 1 & 2 are in-
put from the transceiver. Pins 3 & 4 are output to the transceiver. Pins 5 & 6 are the normally-open relay contacts for oper-
ation of the PTT circuit in the transceiver, where required. Some transceivers key their transmit functions by simply
shorting the ground of the microphone jack to the ground of the earphone jack. Others have extra pins in the plug which
attaches to the transceiver. The purpose of pins 5 and 6 in the 6-pin XLR is to short those extra pins in the transceiver con-
nector to shunt it into its transmit mode.
Connections at the transceiver end will vary with the make and model. Pro Intercom will build connecting cable
assemblies for many makes and models of transceivers.
2. In general, the higher the radio transmitter power, the more care must be exercised in setting up the system.
Operating Instructions & Connections
Pro Intercom LLC
PO Box 7035 Algonquin Illinois 60102-7035
Phone: +1 (815) 680-5205 Orders and Tech support: (888) 320-5928 Fax: +1 (815) 526-8689
Printed in USA Rev.2_01.13
(Cont’d on next page)