230kbps (RS-422?) serial port

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Alas, they are *very* different beasts.

LocalTalk uses HDLC framing with special bit encoding to allow clock recovery / The Zilog SCC does all of that encoding/decoding except for the tri-state driver and transformers.

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I had to resort to the 'pedia for clarification:

/ expensive multi-mode (RS-232/RS-422) capable serial ports. The port was driven by the Zilog SCC which could serve as either a standard UART or handle the much more complicated HDLC protocol which was a packet oriented protocol which incorporated addressing, bit-stuffing, and packet checksumming in hardware. Coupled together with the RS422 electrical connections /

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I always gets my layers confuzzled. So physically/electrically the port is both RS-232 and 422 compatible, and HDLC runs on top of the RS-422 mode?

http://en.wikipedia.org/wiki/High-Level_Data_Link_Control

But anyway, I gather your point is that the Zilog controller & associated hardware handles all the physical and data link layer stuff, and it would be far simpler to just use one than try to emulate it in code on a micro.

A quick check at octopart confirms widespread availability of the SCC