On 01/18/2013 01:14 AM, Ian McLaughlin wrote: I'm not working on anything now - I just came up with the idea. I meant "do you design stuff with microcontrollers". I did some Googling, and there seems to be commercial units, all around $1K per end (async is much cheaper). Good heavens! Microcontrollers and digital electronics is another one of my hobbies. Excellent! Same here, though I also do it professionally. Async serial is simple for a microcontroller to handle. I've never actually looked to see if there's any synchronous libraries out there. I'd do it with an HDLC/SDLC-capable chip like a Z8530...offload as much from the firmware as possible, leave those cycles for protocol handling. Unless you meant wrapping bare ?DLC frames in packets? Wrapping the data in UDP is simple. The HDLC layer could deal with error detection/correction. Yes! The problem is finding surplus time to embark on this. Maybe a few of us could collaborate on it? I have that problem as well, but I got really excited when you mentioned it, because I am doing a lot of designs with Ethernet now. I have a "base" design, a "hardware macro" if you will, that I've recycled several times. It's a Philips..erm, NXP LPC2300-series ARM7 with an on-chip Ethernet MAC, and all supporting hardware. I typically run FreeRTOS and uIP on them. Interfacing an ?DLC engine to that would be a cakewalk starting from that base design as a head-start. I have a few tubes of Z8530s in PLCC-44 packages here. -Dave -- Dave McGuire, AK4HZ New Kensington, PA