Clear-Com TW-60 - Manual (Page 12)

T W - 6 0 P U B L I C S A F E T Y R A D I O I N T E R F A C E
2 - 2
commands it. The relay contacts, in conjunction with the cable wiring chosen,
allow for correct transmitter keying to virtually any type of radio.
In addition to the following table, refer to the Block Diagram section of this
manual for a simplified diagram showing the Two-Way Radio connections to the
DB-9F connectors.
WIRING THE TWO-WAY RADIO CABLE
To connect the base-station radio to the TW-60, you must build your own
custom connector cable. This involves several steps:
1. Obtain or make a cable using the kind of plug that fits your radio. Use single
conductor shielded wire for each cable. Miniature type stereo cable is a good
choice. Solder these cables to the DB-9 connector as shown in Example 1.
This cable length should be kept less than 5 feet. A good source of molded
connectors for your radio would be an external microphone or earphone
which can be purchased from your radio supplier. You will need to cut off the
microphone or earphone as it will not be needed.
2. The next step will be to set the type and level of microphone. The TW-60 has
three Setup Switches for each interface channel that can be set for specific
types of microphones. The three illustrations that follow show how the
TW-60 switches and the male DB-9 connector on the channel cable are
configured for most radios. The section that follows, "Setup Switches," gives
instructions for setting the TW-60's Setup Switches.
3. The most difficult setting is often getting your particular radio to key properly.
Every radio has a different method of externally keying its transmitter. To
determine how to set the jumpers and wire the connector, you need to know
what type of external microphone is used in your radio, or you need to
experiment. Below are three examples of how to key the transmitter. If you are
unsure of which wiring to use, try all three, one at a time. Pins 2, 3, 4 and 7
are the relay contacts in the TW-60. If your radio model is not listed in the
addendum sheet and you have tried all three examples, but you still can't
make the two-way radio work properly, call customer service and we will help
you get the system working.
SETUP SWITCHES
Table 3 shows the location of the Setup Switches on the back panel. There is one
set of three for each of the four channels. The switches are set to ON when they
are in the down position and are set to OFF when they are in the up position.
Output Level Switches: Set switches 2 or 3 to ON to lower the signal level to the
two way radio's microphone input. The switches change the levels, as shown in
Table 3. In general, set switch 3 to ON for most low-level mics (for example,
electrets): set both switches 2 and 3 ON to further reduce the input level for
dynamic type mics.