This page is obsolete.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 plugfunctionmeasure
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
5 <-> 3 - Base GND 0V

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.