Optelecom 9522A Installation And Operation Manual page 30

 Set the Clear to Send Inhibited by Optical Side Activity as explained in the Clear to Send Inhibited by
Optical Side Activity section of System Architecture by setting S2-6. Refer to Table 7.
Table 7 — Switch S2, CTS Optical Activity Set
1 2 3
 Set the Ring Propagation Timeout as described in the Ring Propagation Timeout section of System
Architecture on S2-7 and S2-8. Note that the Ring Propagation Timeout plays a role in the ECHO CANCEL
Feature and RS485 2-Wire Operation as explained in System Architecture. This timeout is not important
unless the unit is operated in Master Fault Tolerant Mode and the ECHO Cancel is enabled (S1 switch #7 is
set to the DOWN position). This timeout should exceed the time it takes for a signal to travel from the
master unit around the ring and return to the master unit. To calculate the time, figure (100 nsecs plus 6.5
msecs) times (the number of local modems around the ring) plus (1.5 nsecs per foot of fiber in the ring).
For example, for a ring with a total length of 3000 feet with 15 local modems, the propagation time would
be 0.1 msecs + 97.5 msecs + 4.5 msecs = 102.1 msecs. For this ring, the shortest timeout of 1 msec can
be chosen. Refer to Table 8.
Table 8 — Switch S2, Timeout/Streaming/Priority Select/CTS/Ring Propagation Set Up
1 2 3
 Make the Data Port Connections
RS232 Connections
Data port connections for the two DB25S connectors on the front panels are as shown in Table 9 and
Figures 9 and 10 below. The RS232 connector is wired internally as a DCE (Data Communications
Equipment) device. Note that the connections for both the Primary and Data port are identical.
Connect both the master controller CPU and each local terminal's communications port via the Primary or
Secondary Data Port (DB25S) on the Model 9522Y modem. The only required connections between the
terminal equipment and the modem are pins 2 (Data Input), 3 (Data Output), and 7 (Signal
Return/Common). If the RS232 anti-streaming feature is used it will also be necessary to connect pin 4, the
RTS input. If the terminal equipment requires a high (True) CTS input in order to transmit data, connect
pin 5 of the terminal equipment to pin 8 (CD) of the modem. The CD output is always high.
4 5 6
Up
Down
4 5 6
Up
Down
Down
7 8 Function
CTS Low upon Optical Activity — Enabled
CTS Low upon Optical Activity — Disabled
7 8 Function
Up Ring Propagation Timeout 1 ms.
Up Ring Propagation Timeout 4 ms.
Down Ring Propagation Timeout 12 ms.
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