18
TMAA01-01 Line-Interface Board
TM8100/TM8200 Accessories Manual
© Tait Electronics Limited
August 2005
2.
Set the DIP switches on the line-interface board (S1) to the following
default test settings:
■
DIP1 on (two-wire audio interface)
■
DIP2 off
■
DIP3 off
■
DIP4 on (busy/gate = rx-gate)
■
DIP5 on (busy/gate logic active high)
■
DIP6 off
■
DIP7 off (two-wire keying)
■
DIP8 off (time delay disabled).
3.
Disassemble the radio in order to gain access to the options cavity. For
detailed disassembly instructions, refer to the disassembly procedure
in the service manual.
Note
When installing the internal options loom, take care that it is
folded in the way shown in
Figure 2.2
.
Connect the internal options loom between SK2 on the line-inter-
face board and SK102 on the radio’s main PCB.
4.
Set up the test equipment shown in
Figure 2.1
, and follow the adjustment
procedure for RV1, RV2 and RV3 described in the following section.
2.2.4
Adjusting RV1, RV2 and RV3
Setting the Keying
Time Delay (RV1)
The keying time delay circuit is used to prevent the burst of noise occurring
before a mobile is able to mute the audio when the carrier signal disappears.
The keying time delay is used in conjuction with the keying signal
(SK1 pin 1).
Set DIP8 on, and adjust RV1 for the required time delay. Rotate RV1
clockwise to increase the delay, and counterclockwise to reduce the delay.
Note
If the W1 link is fitted, the maximum time delay available is
reduced from 5 seconds to approximately 2.5 seconds.
Table 2.3
Line-interface settings in the Programmable I/O form, Audio tab
Rx/PTT Type
Tap In
Tap In Type
Tap In Unmute
Tap Out
Tap Out Type
Tap Out Unmute
Rx
None
A-Bypass In
On PTT
R7
D - Split
Busy Detect
EPTT1
T5
A-Bypass In
On PTT
None
C-Bypass 0
On PTT
Table 2.4
Line-interface settings in the PTT form, External PTT (1) tab
Field
Setting
Advanced PTT
PTT Transmission Type
Voice
Audio Source
Audio Tap In
