Siemens SIMATIC TIWAY 1 - Manual (Page 80)

THE TIWAY I NETWORK PORTS
UNILINK HOST ADAPTER 4-6
USER MANUAL
Table 4–3 RS–232–C/RS–423–A “D” Connector Pin Assignment
Interchange
Circuit
Connector
Pin No.
CCITT Description
AA 1 101 Protective Ground
Signal Ground
Transmitted Data
Receive Data
Request To Send
Clear To Send
Data Set Ready
Data Terminal Ready
Recieve Line Signal
Detector
Transmitter Signal
Element Timing
Reciever Signal
Element Timing
102
103
104
105
106
107
108/2
109
114
115
7
2
3
4
5
6
20
8
15
17
AB
BA
BB
CA
CB
CC
CD
CF
DB
DD
The line drivers and receivers meet the requirements for the RS–423–A and
RS–232–C standards. The modem interface is user–selected for either
asynchronous or synchronous operation at data rates of 110, 150, 300, 600,
1200, 2400, 4800, 9600, 19.2K, 38.4K, 57.6K, and 115.2K bits per second.
Modem interface circuits can be longer than the 25,000 feet limit of the Local
Line interface. This interface must be used for cross-building or cross-town
circuits. The modems used must be non-intelligent and have data transparency.
Non-intelligent refers to the class of modems that do not have an internal
command set. Modems such as the Hayes Smartmodem

and compatibles do
have an internal command set and should not be used. Generally, modems that
meet the Bell 103, 202, and 208 specifications will work, but the Bell 212A class
modems will not. In addition to being non-intelligent, the modems must support
data transparency which means no start bits, no stop bits, and no parity. This is
necessary because TIWAY I uses the bit-oriented HDLC protocol to transfer
information between devices. Most short haul modems are non–intelligent and
provide data transparency.