Arcom SBC104, Technical Manual

Page: 24 / 36

COM1 and COM2 Connections
In RS232 mode the two serial communications ports have a pin-out as standard. The SBC104 has
the link selectable option of RS-485 on COM2. The only two signals implemented are DATA+ and
DATA-. This provides half duplex operation only. The RTS signal from COM2 is used to enable
transmission. The receive input is enabled permanently when in RS-485 mode. Do not use any of the
other pins apart from GND, DATA+ and DATA- when using COM2 in RS-485 mode.
RS-485 Configuration
The RS-485 groundline should be connected between the units. The terminating resistor (LK10)
should be selected if the SBC104 is at the eenndd of the cable.
Keyboard Connection
The SBC104 will interface to a standard PC-AT keyboard. A 5-pin DIN to 6-pin ‘Mini’ DIN plug adapter
cable is required.
2192-08704-000-000
Page 24
J562 SBC104
1
9
8
7
6
5
4
3
2
GND
DTR
TXD
RXD
DCD
DSR
RI
CTS
RTS
1
9
8
7
6
5
4
3
2
DATA -
DATA +
RS-232 RS-485
GND