User's Manual

Optimizing MPI 6000 Reader System Performance
5-7
Because the TDM signals are based on RS
–485 signals, you can extend the length of
the TDM bus by using RS
–485 repeaters or by using fiber with converters. Either of
these two modifications should be used only when absolutely necessary in situations
where the TDM lengths need to exceed the 1000-foot (305-m) maximum distance.
Table 5-2 shows the pin designations and descriptions for the TDM connector.
To
implement TDM, you must configure only one reader in the group as a mas
ter
reader for the TDM function. This reader will have a slightly shorter synchronization
period than the rest of the readers connected to it.
Note: T
he TDM synchronization period is set in 1.0-millisecond increments, whereas
the TDM delay and TD
M duration are set in 0.5-millisecond increments.
Figure 5-3 illustrates a typical plaza configura
tion using TDM. There are three
time
slots with three uplink frequencies. All the readers are configured with a
downlink fre-
quency of 916 MHz.
Table 5-2 TDM Connector
Pin Name In/Out Description Recommended Connection
1 N/C N/A No connection N/C
2 N/C N/A No connection N/C
3 N/C N/A No connection N/C
4 N/C N/A No connection N/C
5 N/C N/A No connection N/C
6 N/C N/A No connection N/C
7 TDM (+) In/Out TDM synchronization positive Connect all red pin 7 wires
together.
8 TDM (-) In/O
ut TDM synchronization negative Connect all black pin 8 wires
together.
9 N/C N/A No connection N/
C
PRELIMINARY