Rs-232 Settings And Information - Brainboxes PX-101 Product Manual

These settings are especially helpful when CTS and DSR are not physically connected (such as in a 3
wire setup) and it is not acceptable for the data flow to stop and start due to arbitrary variances on the
unconnected signal lines.

2.8. RS-232 Settings and Information

Note - this section is for RS-232 products only.
RS-232 Standard
The RS-232 standard was introduced in 1962, it is now widely established. RS-232 is a slow speed, short
distance, single ended transmission system (i.e. only one wire per signal). Typical RS-232 maximum cable
length is 50 feet.
9 Pin D Serial Port RS-232 Cables
To connect to the RS-232 Serial Port you will need a cable terminating in a 9 way female D connector. It is
sound practice to use cables with screws fitted that will allow you to fasten the cable securely to the PC card.
In general, you will need to make up a "cross-over" cable to correctly interface the PC to the RS-232 port of
another computer or device. Provided you have the pin outs and handshake requirements of both sides of
your RS-232 connection, the cross over cable becomes a matter of common sense. The cross-over cable is
simply to ensure that the right signals going out of one RS-232 port go into the appropriate lines of the other
RS-232 port.
Pin D Serial Port Connection To Another PC
Suppose we want to connect the Brainboxes Serial Port to the serial port of another PC. Connect the earth
lines. Line 5 of Serial Port 2 to lines 1 & 7 of the other PC. This gives the two devices a common earth level.
Connect the Transmit and Receive lines together. Line 3, TXD, Port 2 goes to line 3, RXD, of the other PC.
Line 2, RXD, Port 2 goes to line 2, TXD, of the other PC. This allows each to receive the data transmitted by
the other.
PX Range Product Manual Version 2.3 © Copyright Brainboxes Limited 2013 Page 23 of 45