B&B Electronics 232MSS2 manual Serial Data Configuration, Smart Switch Operation

Table 3. DTE MASTER PORT CHART

Master Port				A,B,C & D Ports
	(DTE)		Signal		(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	<----->

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

Documentation Number 232MSS2-0108 Manual 5

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