Product description 
 
Application Module FM 458-1 DP - User Manual  2-35 
A5E01078222-02     Edition 03.2009 
2.3.4 Connection possibilities 
EXM 448
LE-BUS
SIMATIC P-BUS
9 pin
Connector assignments:
RS 232 (download)
TxD = 2
RxD = 7
Grd = 1
RS 485 (PROFIBUS)
+Tx/Rx = 3
 -Tx/Rx = 8
Ground 5Vexternal = 5
5Vexternal = 6
PROFIBUS-DP
MASTERDRIVES-
option module
 
Fig. 2-7  Connection possibilities for the communications expansion module  
EXM 448 
An additional expansion module (EXM 438-1 or  
EXM 448/EXM 448-2) can be inserted at this 5 x 24 pin socket connector. 
The 5 x 17 pin socket connectors is used to connect to the SIMATIC S7 
backplane (only power supply). 
The following connections are provided at the 9-pin sub-D socket: 
  PROFIBUS interface with RS 485 format with electrical isolation 
(floating) 
  Parameterizing- and diagnostics interface with RS 232 format to 
download the bus configuration 
  5V power supply for the Optical Link Module (OLM)  
with electrical isolation 
Connecting 
diagram 
LE-bus connection 
P-bus connection 
PROFIBUS-DP (X1)