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15.3
Date Code 20171006
Instruction Manual
SEL-400 Series Relays
Communications Interfaces
Serial Communication
The EIA-232 ports are standard female 9-pin connectors with the pin numbering
shown in
. The pin functions are listed in
. Pin 1 can pro-
vide power to an external device.
Figure 15.2
Example 3U Rear-Panel Layout
Figure 15.3
Example 4U Rear-Panel Layout in Relay With Bay Cards
Figure 15.4
EIA-232 Connector Pin Numbers
Table 15.2
EIA-232 Pin Assignments
Pin
Signal Name
Description
Comments
1
5 Vdc
Modem power
Jumper selectable on
PORT 1
–
PORT 3
. No connection on
PORT F
.
2
RXD
Receive data
3
TXD
Transmit data
4
+IRIG-B
Time code signal positive
PORT 1
only. No connection on
PORT F
,
PORT 2
, and
PORT 3
.
5
GND
Signal ground
Also connected to chassis ground.
6
–IRIG-B
Time code signal negative
PORT 1
only. No connection on
PORT F
,
PORT 2
, and
PORT 3
.
7
RTS
Request to send
8
CTS
Clear to send (input)
8
TX/RX CLK (for
SPEED := SYNC,
only available when
PROTO := MBA or MBB)
Transmit and receive
clock (input)
Rear-panel serial ports only
9
GND
Chassis ground
i3359c
Ports 1 – 3
i3359c
Ports 1 – 3
5 4 3 2 1
9 8 7 6
NOTE:
Pins 5 and 9 are not intended to
provide a chassis ground connection.
Summary of Contents for SEL-421-4
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