On Sat, 3 Jan 1998 14:53:44 -0500 Herbert Graf <hgraf@GEOCITIES.COM>
writes:

>        I was wondering if you could send me the info yoy have on
>DMX512, protocol
>specs, timing diagrams, schematics, hardware details, anything really.
>Thanks for any info. TTYL
>


        A good source for this info is "Recommended Practice for DMX512"
by Adam Bennette.  As I recall, info on ordering it is available at the
USITT web site.
        Here's a quick summary...

Connector
        5 pin XLR
                1 - shield
                2 - data complement
                3 - data true
                4 - spare data complement
                5 - spare data true

        Electrical Levels
                EIA 485 (0 volts and 5 volts), 120 ohm characteristic
impedance

        Data rate
                250 Kbps

        Byte format
                1 start bit
                8 data bits
                no parity
                2 stop bits

        Frame format
                break - 88uS min
                mark after break - 8 uS min
                Start code (generally 0x00) - 1 byte
                Data bytes - 24 (min) to 512
                Mark before break - 8uS min (corresponds to 2 stop bits
of last byte)


Harold