Modem Settings Required For An 11-Bit Modem; Pin Assignments For A Null Modem Adapter And A 25-Pin To 9-Pin Adapter - Siemens SIMATIC S7-200 System Manual

Setting Up Communications Hardware and Network Communications
This configuration allows only one master device and supports only the PPI
protocol. In order to communicate through the PPI interface, the S7-200 PLC
requires that the modem use an 11-bit data string. In this mode, the S7-200
controller requires one start bit, eight data bits, one parity bit (even parity), one
stop bit, asynchronous communication, and a transmission speed of 9600/19,200
baud. Many modems are not capable of supporting this data format. The modem
requires the settings listed in Table 7-4.
Figure 7-20 shows the pin assignments for a null modem adapter and a 25-pin to
9-pin Adapter.
Table 7-4

Modem Settings Required for an 11-Bit Modem

Modem
8 data
1 start
11 Bit 11-Bit
1 stop
1 parity (even)
Null Modem Adapter
Modem
25-pin
Figure 7-20
7-26
Transmission
Data Format
Speed between
in Bits
Modem and PC
9600 baud
19 200 baud 19,200 baud
25-pin
2 2
3 3
4 4
5 5
6 6
7 7
8 8
20 20

Pin Assignments for a Null Modem Adapter and a 25-Pin to 9-Pin Adapter

Transmission
Other Features
Speed on
the Line
Ignore DTR signal
No hardware flow
9600 baud
control
19 200 baud 19,200 baud
No software flow
control
25-Pin to 9-Pin Adapter
PC/PPI cable
25-pin 9-pin
2 2
3 3
4 7
7 5
S7-200 Programmable Controller System Manual
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A5E00066097-02