Service manual

5-1
March 2000
Part No. 001-3139-502
CENTRAL DE-MULTIPLEXER MODULE (CDM)
SECTION 5 CENTRAL DE-MULTIPLEXER MODULE (CDM)
5.1 GENERAL
The Central De-Multiplexer Module (CDM), in
the Local Site, receives the multiplexed data from the
Remote Site RMM or directly from the RDM at the
Local Site and de-multiplexes the information to the
appropriate line to send to the RVMs.
A CDM is connected to each Remote Site RMM,
therefore, 96 CDMs are the maximum number for a
Voter System. A CDM is not required for the Local
Site RDMs, these are hard wired to the RVM.
The CDM is installed in a card rack located near
the Voter. The CDM is powered by +5V DC, -5V DC,
+12V DC and -12V DC. The CDM operates in the
-30°C to + 60°C (-22°F to +140°F) temperature range
with 10 to 90% humidity.
5.2 INPUT DATA
The CDM receives the Data Packet from the
Remote Site Receiver Multiplexer Module (RMM).
The input is 1200 baud RSSI with FSK audio data.
The CDM can only de-multiplex the Data Packet
received from one RMM. The packet contains infor-
mation for each of the 10 possible output lines. The
information for the RSSI has the first 4-bits to define
the line number and the second 4-bits to indicate the
RSSI level, see Table 5-1.
5.3 OUTPUT DATA
The CDM sends the RSSI information to the
RVMs via the RS-232 output ports at 1200 baud.
The data is routed to the appropriate output port
according to the received line number associated with
the data.
Figure 5-1 CDM BLOCK DIAGRAM
Table 5-1 CDM RSSI INFORMATION
Hex Value DESCRIPTION
7
6
5
4
Strongest RSSI signal level
Weakest RSSI signal level a call will be
started at
3
2*
1
0*
Weakest RSSI level before a call will be
dropped.
Receive Time-Out from RDM
No Data received from RMM or RDM
Turn-off Code from mobile was received
* Idle state.