Siemens TC12 Installation, Commissioning And Maintenance Handbook page 38

1. SW1 - Mode Select switch
Ensure that the Mode Select switch is set correctly; see Table 1 for
settings. One of the modes shown is selected on a 7-way DIL switch.
Note NO other settings are to be used in the UK.
2. SW2, SW3, SW6 and SW7 - Line Level switches
Ensure that the Line Level switches are set correctly see Table 2 for
settings). Table 2 shows switch settings corresponding to the different
levels. Each modem PCB contains four DIL switches. SW2 and SW3 are
8-way DIL switches, used for setting the line levels for modem 1 and 2
respectively. SW6 and SW7 are 6-way DIL switches used for setting the
line levels for modem 3 and 4.Positions 1 to 4 of all four switches set the
Output Power and positions 5 and 6 set the Receive Threshold. Position
7 and 8 on SW2 and SW3 are unused. Table 2 shows the setting for the
8-way DIL switches, ignore columns 7 and 8 for the 6-way switches.
For UK use the output power is always set to -13dBm and the receive
threshold is set to -39dBm.
Note: NO other setting except for -13dBm is to be used in the UK.
3. SW4 - 2/4 Wire Selector switch (SW4).
Ensure that the 2/4 Wire Selector switch is set correctly (see Table 3 for
settings).
4. SW5 - Transformer Select switch.
Ensure that the Transformer Select switch (SW5) is set correctly (see
Table 4 for settings). In a radial system (i.e. for any modem connecting to
a transformer board, the switch is set to off board transformers. For all
modems not connected to transformer boards, on board transformers are
selected.
The PCB is fitted with a cover (part number 667/2/22642/000 top, /001 rear). This
cover must ALWAYS be fitted before any connectors are attached to the PCB and
should NEVER be removed whilst any cables are connected to the PCB.
Each Modem PCB has a 14-way ribbon cable (part number 667/1/22643/000) and
a 24-way cable (part number 667/1/22640/000):
The 14-way cable connects the middle header (PL2) on the Modem PCB to the
appropriate 14-way header on the PSU PCB, as follows:
666/HE/43100/000
TC12 Installation, Commissioning & Maintenance Handbook
Connector PL2
Modem PCB 1 -> PL8 on the PSU PCB
Modem PCB 2 -> PL7 on the PSU PCB
Modem PCB 3 -> PL6 on the PSU PCB
Modem PCB 4 -> PL5 on the PSU PCB
Page 28 Issue 10