Siemens TC12 Installation, Commissioning And Maintenance Handbook page 81

3.2.3.4 RS232 Cable
The RS232 cable (667/1/22611/000) supplied with the OTU has flying leads at the
data transmission end of the cable and a keyed 14-way Berg connector at the
OTU end of the cable.
The OTU to data transmission system serial interface complies with RS232 at the
OTU connector using the signals and pin allocations defined in the following table.
Name Direction
TX From OTU
RX To OTU
RTS From OTU
CTS To OTU
CD To OTU
DSR To OTU
DTR From OTU
GND -
NOTES
1. If the data transmission system cannot provide CTS then the cableform
between the OTU and the data transmission system is to provide an RTS / CTS
loopback at the OTU.
2. CD may or may not be provided by the transmission system. It is important that
if CD is provided then it is activated 8ms prior to the start of received data.
If the data transmission system cannot provide CD then GRX=1 handset
command should be used.
3. The DTR signal is maintained at an active state by the OTU at all times except
when the modem mode is changed e.g. GMM handset command. The OTU does
not check for the OTU modem asserting DSR in order to start data transfer to the
Instation.
The Berg connector pin out viewed from the front of the connector (socket side) is
shown below.
NC 1
NC 2
666/HE/43100/000
TC12 Installation, Commissioning & Maintenance Handbook
Pin Notes
6 Transmit Data
10 Receive Data
7 Request to Send - activated by the OTU when it has
data ready for send to the data transmission system
9 Clear to Send - activated by the data transmission
system in response to RTS from the OTU - see note
1
8 Carrier Detect - activated by the data transmission
system in response to a carrier signal - see note 2
- Not used
5 Data Terminal Ready - see note 3
4 Signal Ground
3 5 7 9
4 6 8 10
Page 71
NC
NC
NC = not connected.
Issue 10