B&B Electronics 232MSS2 - Manual (Page 9)

Documentation Number 232MSS2-0108 Manual 5
B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104
B&B Electronics Ltd – Westlink Commercial Park – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445
The 232MSS2 supports the following RS-232 signals: TD, RD,
SG, RTS & CTS.
NOTE: Handshake lines DSR and DTR are tied together on
each connector and are not passed through to the master port. All
other lines are not connected.
The Mini Smart Switch selects port A as the default port at power
up.
Serial Data Configuration
In order for the host device that is connected to the master port
to select any of the four ports, the Mini Smart Switch must be set to
match the host's communication format. Dipswitch “SW1” is used to
select the communication format of the Mini Smart Switch. Switch
positions 1 through 3 select the baud rate. Switch position 5 selects
7 or 8 data bits. Switch position 6 determines if parity is enabled or
disabled.
NOTE: A data format of 7 data bits, no parity and one stop is
not allowed.
Switch position 8 selects the port configuration, see section titled
"Port Configuration". Refer to Table 1. Always power down the smart
switch when changing switch settings.
Smart Switch Operation
Smart Switch mode is selected when dipswitch “SW1” position 7
is “Off.” In Smart Switch mode, the 232MSS2 is constantly looking
for the three character preamble code by monitoring the data that is
being received on the master port from the host device. The
232MSS2 requires a three character preamble code to turn on and
off a port. The first character must be the ASCII escape character
(decimal 27). The second character is user programmable by setting
dipswitch “SW2”. “SW2” comes from the factory programmed to the
Table 3. DTE MASTER PORT CHART
Master Port
(DTE) Signal
A,B,C & D Ports
(DCE)
Pin# Direction Description Pin# Direction
2 Output Transmit Data (TD) 3 Input
3 Input Receive Data (RD) 2 Output
4 Output Request to Send (RTS) 7 Input
5 Input Clear to Send (CTS) 8 Output
7 <-------> Signal Ground (SG) 5 <----->