Interface Switch; Switch Function - NCR 7890 User Manual

Switch Function

Interface Switch

The 7890 Scanner includes circuitry for all available
interface options. However, the interface switch must
match the communication protocol programming.
The interface switch selects the active interface by
selecting the circuits to the Interface Connector. To
change between OCIA and RS-232 or IBM 468x, you
must change the setting of the interface switch. When
the switch is in the Out position, the OCIA interface is
selected; when the switch is in the In position, the RS-
232 and IBM 468X interface is selected. The following
chart gives the Interface Connector pin assignment
selected by the Interface Switch.
Pin Switch Out
Number OCIA
1 +9 Vdc
2 +5 Vdc RTN
(from host)
3 SDATA/
4 CLKOUT/
5 CLKIN/
6 RDATA
RTN
7 RDATA/
8 GND
User's Guide
Troubleshooting Your 7890 Scanner
Interface Switch
Switch In
RS-232 IBM 468x
+9 Vdc +9 Vdc
TXD
RXD
TXD
RTS
CTS TERM PWR
RXD
GND GND
6-5