Port configuration – B&B Electronics 232MSS2 - Manual User Manual
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Documentation Number 232MSS2-0812Manual
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
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Port Configuration
In order to determine the proper port configuration of the
232MSS2, it is necessary to have a basic understanding of the terms
DCE and DTE. RS-232 was designed, using DB-25 connectors, for
connecting a DTE (Data Terminal Equipment) device to a DCE (Data
Communication Equipment) device. Each device will have inputs on
pins that correspond to outputs on the same pins of the other device.
For example, a DTE device will transmit data out on pin 2 (on a DB-
25) and a DCE device will receive data in on pin 2 (on a DB-25). IBM
PCs and serial printers are DTE devices, modems are DCE devices.
If an IBM PC (DTE device) is going to be connected to the 232MSS2
master port, the master port should be configured as a DCE port. If a
modem (DCE device) is going to be connected to the master port, it
should be configured as a DTE port.
The master port can be configured as a DCE port (data received on
pin 2) or a DTE port (data received on pin 3) by setting dipswitch
“SW1”, position 8. To configure the master port as a DCE port, move
dipswitch “SW1”, position 8, to the "OFF" position. When the master
port is configured as a DCE port, ports A, B, C, & D will become DTE
ports (Refer to Table 2). To configure the master port as a DTE port
move d
ipswitch “SW1”, position 8, to the "ON" position. When the
master port is configured as a DTE port, ports A, B, C, & D will
become DCE ports (Refer to Table 3). Always power down the smart
switch when changing switch settings.
Table 2. DCE MASTER PORT CHART
Master Port
(DCE)
Signal
A,B,C & D Ports
(DTE)
Pin# Direction
Description
Pin#
Direction
2
Input
Transmit Data (TD)
3
Output
3
Output
Receive Data (RD)
2
Input
4
Input
Request to Send (RTS)
7
Output
5
Output
Clear to Send (CTS)
8
Input
7
<------->
Signal Ground (SG)
5
<----->