Rear Communication Board; Ethernet Board; Figure 23: Rear Communication Board; Figure 24: Ethernet Board - GE P4A Technical Manual

Chapter 3 - Hardware Design
6.9

REAR COMMUNICATION BOARD

Figure 23: Rear communication board

The optional communications board containing the secondary communication ports provide two serial interfaces
presented on 9 pin D-type connectors. These interfaces are known as SK4 and SK5. Both connectors are female
connectors, but are configured as DTE ports. This means pin 2 is used to transmit information and pin 3 to receive.
SK4 can be used with RS232, RS485 and K-bus. SK5 can only be used with RS232 and is used for electrical
teleprotection. The optional rear communications board and IRIG-B board are mutually exclusive since they use
the same hardware slot. However, the board comes in two varieties; one with an IRIG-B input and one without.
6.10

ETHERNET BOARD

Figure 24: Ethernet board

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P54A/B/C/E
P54xMED-TM-EN-1