This page is obsolete. See GenBoard/Manual/CommConfiguration
How to make the RS232 connector for GenBoard/VerThree
Only 3 wires are needed for the cable.
This is the good pinout. Unfortunately there was a nice looking but bogus (and uneditable) pinout circulating, confusing many users (apparently still hunting).
|DB9||dir||SV2||EC18 (optional)||Earphone plug||function||measure|
|3||-->||1||pin14||RING||Data transmitted from PC => genboard||high impedance input to genboard, so without input connected measured voltage is indefinite, usually close to 0V. If you connect, say 5V through 10k resistor, it will measure 5V|
|2||<--||2||pin15||TOP||Data received by PC, transmitted by genboard||+7..8V or -7..8V|
SV2 is the 3 pin connector next to the MAX232 chip, near the regulator and EC18. Pin 1 on SV2 is the "top" pin, with GND on the side closest to the EconoSeal loom connectors.
Only the SV2 header is populated. The pinout of SV1 is the same. Pin 3 of SV1 is the pin closest to Pin 1 of SV2.
The EC18 pins in the above table (pin 14 and 15) are otherwise free pins where the RS232 signals are often connected to.
DB9 works well but using a 1/4" earphone plug looks cleaner in an automotive enviroment. Even if 3.5mm plugs is used in the Autronic harness their manual recommends using 1/4" plugs if it's installed in a panel. This is a good advice, go with the 1/4" plug. The biggest problem with 3.5mm is that most of the female connectors are low quality and will cause problems with time.
GenBoard/AdvancedComm shows how to extend the range of the the serial link (up to 20000km) for development and tuningsoftware testing purposes.