Siemens 500 NIM - Manual (Page 23)

Network Design Considerations 2-5 SIMATIC TIWAY I Series 500 NIM User Manual
2.2 RS-232-C Cable Installation
The physical layer in TIWAY I provides a modem interface for synchronous
or asynchronous modems at data transmission rates up to 115.2K bits per
second. The modem interface provides standard signals, as defined in
Table 2-1, for control of two-way alternate data transmission using both half
and full duplex modems. The modem interface is a standard “Type E” DTE
configuration as defined in Section 5 of EIA RS-232-C. This interface uses a
male (plug) 25-pin D-type connector on the communication cable. The
circuits and pin assignments for the RS-232-C connector are shown in
Table 2-1.
Table 2-1 RS-232-C Connections
Pin ISO # RS–232-C Name – Function
1 101 AA – Protective Ground (chassis)
2 103 BA – Transmitted Data
3 104 BB – Received Data
4 105 CA – Request to Send (RTS)
5 106 CB – Clear to Send (CTS)
6 107 CC – Data Set Ready (DSR)
7 102 AB – Signal Ground
8 109 CF – Received Line Signal Detector/
Data Carrier Detect (RLSD/DCD)
15 114 DB – Transmitter Signal Element Timing
17 115 DD – Receiver Signal Element Timing
20 108/2 CD – Data Terminal Ready (DTR)