GE UR Series Instruction Manual page 68

3.3 L90 CHANNEL COMMUNICATION
a) RS422: TWO CHANNEL APPLICATIONS VIA MULTIPLEXERS
The RS422 Interface may be used for '1 channel - 2 terminal' or '2 channel - 3 terminal' applications over SONET/SDH and/
or Multiplexed systems. When used in 1 channel - 2 terminal applications, the RS422 interface links to higher order sys-
tems in a typical fashion observing Tx, Rx, and Send Timing connections. However, when used in 2 channel - 3 terminal
applications, certain criteria have to be followed due to the fact that there is 1 clock input for the two RS422 channels. The
system will function correctly if the following connections are observed and your Data Module has a feature called Terminal
Timing. Terminal Timing is a common feature to most Synchronous Data Units that allows the module to accept timing from
an external source. Using the Terminal Timing feature, 2 channel - 3 terminal applications can be achieved if these connec-
tions are followed: The Send Timing outputs from the Multiplexer - Data Module 1, will connect to the Clock inputs of the UR
- RS422 interface in the usual fashion. In addition, the Send Timing outputs of Data Module 1 will also be paralleled to the
Terminal Timing inputs of Data Module 2. By using this configuration the timing for both Data Modules and both UR - RS422
channels will be derived from a single clock source. As a result, data sampling for both of the UR - RS422 channels will be
synchronized via the Send Timing leads on Data Module 1 as shown in the following figure. If the Terminal Timing feature is
3
not available or this type of connection is not desired, the G.703 interface is a viable option that does not impose timing
restrictions.
Figure 3–31: TIMING CONFIGURATION FOR RS422 2 CHANNEL - 3 TERMINAL APPLICATION
Data Module 1 provides timing to the L90 RS422 interface via the ST(A) and ST(B) outputs. Data Module 1 also provides
timing to Data Module 2 TT(A) and TT(B) inputs via the ST(A) and AT(B) outputs.
The Data Module Pin Numbers, in the figure above, have been omitted since they may vary depending on
the manufacturer.
NOTE
3-26
Tx1(+) W 2a
Tx1(-) W 3b
RS422
Rx1(+) W 4b
CHANNEL 1
Rx1(-) W 3a
W 6a
Shld.
+ W 7a
CLOCK
-
W 8b
Tx2(+) W 4a
W 5b
Tx2(-)
RS422
W 6b
Rx2(+)
CHANNEL 2
W 5a
Rx2(-)
Shld. W 7b
com W 2b
SURGE W 8a
L90 Line Differential Relay
Data Module 1
Signal Name
Pin No.
SD(A) - Send Data
SD(B) - Send Data
RD(A) - Received Data
RD(B) - Received Data
RS(A) - Request to Send (RTS)
RS(B) - Request to Send (RTS)
RT(A) - Receive Timing
RT(B) - Receive Timing
CS(A) - Clear To Send
CS(B) - Clear To Send
Local Loopback
Remote Loopback
Signal Ground
ST(A) - Send Timing
ST(B) - Send Timing
Data Module 2
Signal Name
Pin No.
TT(A) - Terminal Timing
TT(B) - Terminal Timing
SD(A) - Sand Data
SD(B) - Sand Data
RD(A) - Received Data
RD(B) - Received Data
RS(A) - Request to Send (RTS)
RS(B) - Request to Send (RTS)
CS(A) - Clear To Send
CS(B) - Clear To Send
Local Loopback
Remote Loopback
Signal Ground
ST(A) - Send Timing
ST(B) - Send Timing
831022A2.CDR
GE Power Management
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