Siemens Simatic 620 - Manual (Page 142)

Hardware Information
7-10
SIMATIC Box PC 620 Manual
A5E00131465-01
Serial Port COM1 (PLC/V.24/Modem) *
The serial port (COM 1) on the Box PC has the following pinout:
1
13
14
25
Figure 7-1 COM 1 Serial Port (Socket Connector)
Pin No. Designation Description Input /Output
1 - Shield -
2 TxD (D1) Serial transmit data Output
3 RxD (D2) Serial receive data Input
4 RTS (S2) Request to send Output
5 CTS (M2) Clear to send Input
6 DSR (M1) Data set ready Input
7 GND (E2) Functional ground
(reference potential)
-
8 DCD (M5) Data carrier detect Input
9 +TTY RxD TTY receive Input
10 - 17 - Unassigned -
18 +TTY TxD TTY send Output
19 +20mA Isolated current source -
20 DTR (S1) Data terminal ready Output
21 -TTY TxD TTY send Output
22 RI (M3) Incoming call Input
23-25 - Unassigned -
* The line current (TTY) interface is an optional product feature.