The GW132 RS232 Serial Line Driver is designed for use with Personal Computers and Peripherals, allowing the usual distance limitations associated with RS232 serial communications to be overcome. There are no switches to set, all data is transparent to the units and no power supplies are necessary as the GW132 is line powered from the handshake signals.
Maximum range up to 500 metres, and extension cables are available. Maximum 19200 Baud, greater for shorter range.
Transformer Isolated to 500V DC.
Ensure the equipment is turned OFF. Remove the lead between the equipment and replace with the GW132 Serial Line Driver. Turn the equipment back ON and you are ready to communicate.
The GW132 is available in two formats:-
9 Pin Female D connector, compatible with PC 9 PIN Serial Port. GW132/9F
25 Pin Female D connector, compatible with PC 25 Pin Serial Port. GW132/25F
"In troubleshooting any RS232 link, a pair of RS232 breakout boxes may be useful".
My pair of GW132's are not working - what's wrong?
The GW132 are designed as a low cost easy to use isolated line driver, but installation is not always trouble free. If you install the link and you have no signs of life then you may have one of the following problems:
1/ The cable connecting the two devices isn't installed correctly - see 'Extending the link cable'
2/ One end of the link or the other is not being powered by the equipment it is plugged into - see 'Powering a GW132'
3/ The link speed is to slow/fast for the GW132's - the GW132's operate between 300 Baud and 19200 baud. Set your equipment to a suitable speed.
4/ At either end of the link the RS232 signals are the wrong way around for the GW132. Check Appendix A - RS232 pinout.
5/ It is rare but not unknown for a GW132 to be not working - try a very basic link, like the one in the section 'How can you tell if the link is working?', if you suspect any problems.
How can you tell if the link is working?
One way of checking whether a GW132 link is working is to connect the two GW132s to 2 PCs and use a terminal program like Hyperterminal which is supplied with Windows. Run Hyperterminal and select the Com port that the GW132 is plugged into, select a baud rate between 1200 and 19200 baud. Any characters typed should appear on the screen of the other PC.
If you only have 1 PC available at one end of the link then power the other end on the link as described in 'Powering a GW132' and join pins 2 and 3 together. Run Hyperterminal, to reduce the risk of confusion, make sure 'local echo' is turned off by going to Files -> Properties and then selecting the settings tab, click the Ascii Setup button and make sure that 'Echo typed characters locally' is unchecked. Any characters typed should appear on the terminal screen.
Extending the link cable.
RJ45 cables and couplers can be bought (or made up in the case of cables) as either straight, where pin 1 at one end goes to pin 1 at the other, of cross over , where pin 1 goes to pin 8. The supplied cable couplers are 'cross over' types. With this coupler the link will work as the Rx+ signal at on end will be connected to the Tx+ at the other.
To extend the line you need to make sure that these connections are maintained, a good way of doing so is to make sure that there is always an odd number of crossover components in the link. So using the GW132's out of the box with one crossover coupler will work and so will using the 2 crossover couplers supplied and a crossover extension lead, but not the 2 crossover couplers and a straight lead.
Powering a GW132
The GW132 will normally draw power from the hardware handshake lines of the equipment to which it is attached. If Hardware lines are not available then the only other option is to provide power through the RS232 connector.
If for any reason hardware handshakes are not available for a GW132 to use to power itself, then power can be fed into the GW132 through the RS232 connector. A voltage of between 5 and 12 Volts can be applied to the pins given below.
25 way connector -
GND - Pin 7.
V+ - Pins 20, 6, 5, 4.
9 way connector -
GND - Pin 5.
V+ - Pins 4, 6, 7, 8
Appendix A - RS232 Pinout.
25 way connector -
2....... RxD Data receive
3....... TxD Data transmit
A handshake signal on any of the pins marked PWR will power the device.
9 way connector -
2....... TxD....Data transmit
3....... RxD...Data receive
* = connected to loop back handshakes
Appendix B - GW132 RJ45 connector Pinout
If viewed with the RJ45 contact surfaces facing you, contacts at the bottom and wire at the top, pin 1 is on the right. Only the middle 4 contacts are used.
1 ....................NC - No connection
2 ....................NC - No connection
3.................... TX+ - Transmit positive
4.................... TX- - Transmit negative
5 ....................RX- - Receive negative
6.................... RX+ - Receive positive
7.....................NC - No connection
8.....................NC - No connection