Serial Port (sled vs empeg)

Posted by: Shonky

Serial Port (sled vs empeg) - 30/04/2002 01:28

OK, from hunting around I know that the remote turn on wire appears at pin 4 (DTR) of the sled serial port. I am looking to power a simple RS232 level converter (and some other minor circuitry) off the remote wire. Can someone tell me how much current/power I can draw from the empegs amp remote line? I'm only looking at say 100-200mW.

If possible I'd like to get away without finding a voltage regulator with an inhibit line and just running a standard regulator off the amp remote line.

In the final system I would have the amp remote wire going to 1 regular amp, the remote line of my cd changer and powering a MAX202 based circuit.

Also can someone confirm or deny whether or not the serial port on the sled is different to the empeg one? I know for sure the port on the empeg is PC type (i.e. DTE). I have seen mention that the sled is opposite (i.e. DCE) but it is setup for connecting to GPSes etc. This doesn't make sense to me since I would expect a GPS to be the DCE device. I have to rip my dash apart to find out, but I need to know before I can lay out the board.

Thanks guys,
Posted by: altman

Re: Serial Port (sled vs empeg) - 30/04/2002 01:40

The amp remote line needs to power the tuner, ISTR this is around 100-200mA @ 12v. A decent amp will draw no more than ~5mA from the remote line as it will just turn a mosfet switch on.

The amp remote line is rated at 1A. It's fused with a resettable fuse, and the high-side driver that switches it is overcurrent/overtemperature protected too. Just try it and see if it works.

Hugo
Posted by: Shonky

Re: Serial Port (sled vs empeg) - 30/04/2002 02:35

Well I'm replying to my own post, but someone else might want to know too.

The sled serial port is definitely a DCE. i.e. it transmits on the RX pin meaning a straight through connection to a PC but a null would be required for connecting to most serial type "peripherals" in the car.