Barnett Engineering B1474 Operation Manual page 16

To operate full duplex, leave SW2.8 OFF. To operate half duplex, set switch SW2.8 ON. If a
2 wire circuit is used, the modem will only operate half duplex.
RTS Con trol
SW3.1, when ON, will assert RTS continuously. This causes PTT to be asserted and transmit
tones to be generated. The switch should be on for a no handshaking, non-buffered
configuration. The continuous RTS is also useful for testing purposes.
Buffer
If hardware handshaking is desired, connect the RTS and CTS signals to the DB-25S connector
and set SW3.2 OFF. If XON/XOFF control (software handshaking) or no handshaking with full
buffering is desired, set SW3.2 ON and remove connections from the RTS and CTS positions in
the DB-25S connector.
2/4 Wire
Set SW3.3 and SW3.4 OFF if 4 wire communications are used. Set SW3.3 and SW3.4 ON if
2 wire communications are used. If a 2 wire circuit is used, the modem will only operate half
duplex.
(4) Re place The Top Cover
Place the top cover back onto the base and tighten the two center screws.
(5) Ap ply Volt age
Apply the proper voltage to the unit. If the LEDs are enabled, the run lamp will illuminate,
indicating that power is available at the modem.
B1474 BARNETT EN GI NEERING LTD. PAGE 15