Serial Port Specifications - Hitachi EHV+ Series Applications Manual

2.3.3 Serial port specifications

(1) RS-232C
Direction
Pin Signal
No. name
CPU
1 SG
2 CD
3 ER1
4 ER2
5 SD
6 RD
7 DR
8 RS
[1]SG
[2]CD
[3]ER1
[4]ER2
[5]SD
[6]RD
[7]DR1
[8]RS
Figure 2.1 Circuit diagram and Pin No. of RS-232C
Table 2.6 List of signal of RS-232C
Meaning
Host
Signal ground
Carrier Detect signal.
When CPU is ready to communicate, this signal is high.
Always high
Sending data from CPU
Receiving data to CPU
When this signal is high, connected device is ready to communicate.
When CPU is ready to receive data, this signal is high.
Port from a front view of module
2 – 7
Chapter 2 Specifications
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