TC12 Installation, Commissioning & Maintenance Handbook
The cover must ALWAYS be fitted before any cables are installed, and should
NEVER be removed whilst the telephone cable (from socket SK1 on the PCB) is
connected to the telephone network.
Figure 34 - Integral OTU PCB Layout and Switch Settings
PLA
S2
PLB
Serial
No.
Batter
y
ON/OFF
LP2 - Carrier Detect
LP3 - Transmit confirm
LP4 - Watchdog Fail
SK2 - Reply
Line Jack
Sockets
SK3 - Control
6-Way Telecom Socket
S1 2/4 Wire
Selector
B1
Status
LEDs
S3
Line level
switches
60-Wa
y
connector for
LMU inputs
40-Wa
y
extended
system bus
connector
Lithium Batter
y
SK1 600R / HI-Z
Selector
S4
Covered area. (Cover same shape on bottom of PCB)
Cover fixing
Processor
PLD Firmware
Closed ‘1’
when pushed
up. Open ‘0’
when pushed
down.
(Example
shown open)
2 wire
4 wire
600R
HI-Z
On Off
6.3.2.3 Configuring the Sw itches on the Integral OTU PCB
Before any connectors are attached to the Integral OTU PCB, the configuration
switches need to be set up as described below. Figure 34 shows the position of
the switches on the PCB and the directions to set the switches to for different
options.
There are four switches on the PCB:
S1 - 2/4 Wire Select Switch
S2 - Lithium Battery On/Off Switch
S3 - Line Level Switch
S4 - 600 Ohm/High Impedance Switch
These are set as follows:
1. S1 - 2/4 Wire Select Switch
Set to either 2 or 4 wire (see Figure 34) as required by the position indicated on
the installation sheet for the Integral OTU.
666/HE/43100/000 Page 168 Issue 9