Siemens TC12 Installation, Commissioning And Maintenance Handbook page 181

2.
Set the Lithium Battery Switch (S2) to ON (see Figure 34).
3.
Ensure that the Line Level switch (S3) is set to the required line levels. These are
stated on the installation information sheet for the Integral OTU. Table 8 shows
switch settings corresponding to the different levels. Switch S3 is a 6-way DIL
switch. Switch positions 1 to 4 set the Output Power and switch positions 5 and 6
set the Receive Threshold. Warning - for use in the UK the power level must
not be set to greater than -13 dBm.
4.
Switch S4 - Installation (To be performed by qualified/authorised installation/
service engineer.)
WARNING -
This switch is always set to the 600 Ohms position for all Radial, Multi Point and/or
Multi Terminal lines. The switch is set to 600 Ohms during manufacture and
therefore does not need to be changed. Where British Telecom or other telephone
line supplier has agreed to provide Multi-drop circuits, i.e. where more than one
OTU is to be connected to one line, the final OTU on the line is set to 600 Ohm,
all others on the line must be set to high impedance. Then the switch may be set
as appropriate for the OTU, as noted below.
Note to Service / Installation engineers:
This switch is located underneath the cover. The top half of the cover should be
removed in order to set the switch. No cabling should be connected at this stage,
but before removing the cover make sure that the cable connected to socket SK1
of the PCB is not connected to the telephone network. Ensure the cover is re-fitted
correctly after setting the switch.
Make a note of the switch setting on the OTU installation sheet for future
reference.
5. The PCB can now be replaced back in the card guides.
Set the 600 Ohm / High Impedance line termination Switch (S4) to the setting
indicated on the installation sheet for the Integral OTU (see Figure 34 for switch
positions).
666/HE/43100/000
TC12 Installation, Commissioning & Maintenance Handbook
S2 - Lithium Battery On/Off Switch
S3 - Line Level Switch
S4 - 600 Ohm/High Impedance Switch
THIS SWITCH IS LOCATED UNDER THE PCB COVER. THE
STC WARRANTY WILL BE INVALIDATED IF THE COVER IS
LEFT OFF OR MISSING.
Page 171 Issue 10