1MRS 750107-MUM
Serial LonTalk
Adapter
Technical Reference Manual
SLTA Option Card
ABB Automation
9
5. Interfaces
5.1.
General
The SLTA option card has 5 separate interfaces:
- a 64-pin E1 card connector for connection to the mother board of the
RER 111 unit
- a fibre-optic transceiver pair
- a 9-pin D-type female connector for the RS232 interface
- a service switch
- a 40-position SIMM connector for the LTS-20 core module.
5.2.
RS232 interface
5.2.1.
Specification
The RS232 interface is a 9-pin D-type female connector. This connector can be
wired as a 3-wire interface for the connection to a host or as an 8-wire interface when
it is used in conjunction with a modem.
Communication cables for use with SLTA option card can be ordered separately.
For ordering information, see chapter 9.
The RS232 communication cable has to be shielded. The length of the serial
communication cable is limited to max. 12 m.
It is recommended to connect the shield to ground in one end of the cable. However,
depending on the specific case and the surroundings, the cable may need more than
one earth connection. In such a case the other earth connections should be made
through a capacitor.
To connect the protective shield, note the following instruction. The protective
shield is designed to be connected to the casing of the D-type connector, which has
to be made of conductive material. The connector of the option card is earthed to the
case of the RER 111 unit.
The figure 5.2.1.-1 illustrates the connection of the protective shield to the cable
connector.
Table 5.2.1-1
The pin designations for the RS232 interface
Pin
Signal in DCE mode
Signal in DTE mode
Description
1
DCD OUT
DCD IN
Data Carrier detect
2
TXD
RXD
Data I/O
3
RXD
TXD
Data I/O
4
DTR IN
DTR OUT
Data Terminal Ready
5
GND
GND
Signal Ground
6
DSR OUT
DSR IN
Data Set Ready
7
RTS IN
RTS OUT
Request To Send
8
CTS OUT
CTS IN
Clear To Send
9
RIOUT
RIIN
Ring Indicator
