Radio Shack PRO-2053 owner manual Understanding Trunking, Setting Squelch for the Trunking Mode

available on the Internet, (for example, at www.trunkscanner.com).

UNDERSTANDING TRUNKING

In the past, groups that transmit frequently, such as police departments, could transmit on only a few frequencies. This resulted in heavy traffic and often required 2-way radio users to wait for a specific frequency to clear before transmitting. Trunked systems allow more groups of 2-way radio users to use few- er frequencies. Instead of selecting a specific frequency to transmit on, a trunked system chooses one of several frequencies when the 2-way radio user transmits. The system automatically transmits the call on that fre- quency, and also sends a code that identifies that 2-way radio user's transmission on a control channel.

Your scanner lets you easily hear both the call and response transmissions for that 2- way radio user and therefore follow the con- versation. For EDACS and Motorola (above 406 MHz range), the scanner monitors the control channel between each transmission to identify talk groups.

SETTING SQUELCH FOR THE TRUNKING MODE

Your scanner automatically mutes the audio during trunk scanning when it decodes con- trol channel data. However, we recommend you turn SQUELCH clockwise and leave it set to a point just after the hissing sound stops. This lets the scanner quickly acquire the data channel.

PROGRAMMING TRUNKING FREQUENCIES

You program trunking frequencies the same as non-trunked frequencies, except that you must store the appropriate mode (MOT or ED) with each frequency.

Notes:

•You can scan only one type of trunked frequency, either EDACS or Motorola in a bank. You can, however, mix conven- tional channels and frequencies in a bank.

•If you are programming trunked frequen- cies for Motorola Type I and hybrid sys- tems, you must first program the fleet map (see "“Programming Fleet Maps” on Page 33).

•If you are programming frequencies for an EDACS system you must store them in the Logical Channel Number order (usually listed as LCN#). For example, LCN1 would go into channel 01 for the current bank, and LCN2 would go into channel 02.

Follow these steps to program trunked fre- quencies:

1.Press PROG and press (or hold down) 8 or 9 to select the bank.

	,òòòUôô ôö")
	òôòòòòò
Bank	â8EBýòý á?ýòò

Note: To move through the banks one at a time, repeat the sequence of PROG, FUNC then 8 or9 until you reach the desired bank. To move through the bank selection faster, press PROG then FUNC and hold down 8 or 9.

2.Press TRUNK to enter the ID program mode.

3.Repeatedly press MODE to select )+0 for Motorola, or ! for the EDACS (GE/ Ericsson) system to scan. This sets the

Trunking Operation 31