Table of Contents
Advertisement
2.8.1. Series Mode Installation
Refer to Figure 2-2 and proceed as follows to install the ATT-20 in a series mode
application:
1. Connect a jumper strap between terminals 4 and 6 on the ATT-20 when the total
single conductor cable length from the ATT-20 to the track is less what appears
in Table 2-3 below. If the cable length is exceeded, connect terminals 4 and 6 on
the ATT-20 to terminals 1 and 2, respectively, of the cable compensating circuit
board (N131002-01). The cable compensating PCB is part of an ATT-20 kit. See
Section 6.1 for part numbers.
Suffix No.
Frequency
N451052-
-3904
-3905
-3906
2. Connect terminals 3 and 5 to terminals 3 and 4 of the USSP-21 surge
suppressor.
3. Connect terminals 1 and 2 of the USSP-21 to the track at a point 75 feet from the
switch points. All cabling from the ATT-20 to the track must be #9 AWG or
heavier twisted pair.
4. Connect terminals 7 (relay +) and 8 (relay -) to the relay. The recommended relay
to be used with the ATT-20 is a PN-150B, 400 ohm, plug-in type, Part No.
N322500-701.
5. If the ATT-20 is to receive its DC power from a battery, constant potential rectifier
supply (CPR), or an electronically regulated supply, a surge ripple filter (Part No.
N451590-0301) must be used as follows:
• If the ATT-20 is to be powered from an electronic supply, this supply should
be capable of delivering 1.0 ampere at 12 VDC (on the ATT-20 side of the
surge ripple filter) and be dedicated to the ATT-20 it is powering.
2.8.2. Series Mode Adjustment without Cable Compensating PCB
Proceed as follows to adjust the ATT-20 in a series mode, without cable compensating
PCB installation:
1. Connect a hardwire shunt across the rails 65 feet from the ATT-20 track
connections.
2. Adjust the ATT-20 transmitter output level through the access hole in the top
cover until the relay is just energized.
Copyright 2019
Table 2-3.
Cable Length vs. Frequency
Total Cable Length
(KHz)
(Length x 2 cond.)
12.28
< 75 feet
15
< 50 feet
20
< 25 feet
SM 6299 Rev. 3, March 2019
ATT-20 Audio Track Transceiver
Jumper from Cable Compensating
PCB to Terminal:
T3
T2
T1
2-6
Hide quick links:
Advertisement
Table of Contents
