Today I had small war with 13W3 to VGA adapter. I realize that there are dozens variants of 13W3 wirings (only RGB are in constant place). Each company has its own standard and several of them has more than one... SGI has two variant (without DDC using ID pins and with DDC using I2C interface). There are also several ways of generating sync pulses (H and V separately, H and V xored together - composite sync or mixed with green signal - sync on green). These all variants multiplied by the number of companies gives dozens combinations. There are also ID pins and they can be configured in several ways multiplying number of possible adapter wiring.
I have a question - in the SGI no DDC
13W3 connector there are 4 "
Monitor ID" signals. If I'm right each monitor should set code describing its display capabilities. Using 4 bits it is possible to encode 16 different values. Do You know what each of these values mean?
And second question - are these pins used by graphics hardware, OS or other application? Is it important to set correct ID value?
