TC12 Installation, Commissioning & Maintenance Handbook
3.2.3.4 RS232 Cable
The RS232 cable (667/1/22611/000) supplied with the OTU has flying leads at the
dthe
OTU en
at the
ble.
ata transmission end of the cable and a keyed 14-way Berg connector at
d of the cable.
The OTU to data transmission system serial interface complies with RS232
OTU connector using the signals and pin allocations defined in the following ta
Name Direction Pin Notes
TX From OTU 6 Transmit Data
RX To OTU 10 Receive Data
RTS From OTU 7 Request to Send - activated by the OTU when it has
data ready for send to the data transmission system
CTS To OTU 9 Clear to Send - activated by the data transmission te system in response to RTS from the OTU - see no
1
CD To OTU 8 Carrier Detect - activated by the data transmission
system in response to a carrier signal - see note 2
DSR To OTU - Not used
DTR From OTU 5 Data Terminal Ready - see note 3
GND - 4 Signal Ground
NOTES
data transmission system cannot provide CTS then the cableform
1. If the system is to provide an RTS / CTS
opback 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
between the OTU and the data transmission
lo
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
station.
The Berg connector pin out viewed from the front of the connector (socket side) is
shown below.
In
NC 1 3 5 7 9 NC
NC 2 4 6 8 10 NC
NC = not connected.
666/HE/43100/000 Page 71 Issue 9