>     Guys,
>
>     What about UART's? If you have two pieces of equipment (micros) that
>     need to talk to each other, use a hardware UART. This gives you full
>     duplex asynchronous serial communications. If you build in a SLIP type
>     low level protocol (see RFC1055) you get a modem interface for free,
>     Get your in the field, over the phone insystem programming upgrade
>     here!
>
>     The interface to a PC then becomes a piece of cake with the help of a
>     Maxim MAX202.
>
>     regards
>     SW.
>

        Sorry Scott, not in this environment! the original question
        was for a 16C84 based application, which doesn't have an
        internal UART, adding an external Hardware UART would require
        just about ***ALL*** the available I/O lines on the PIC.
        (8 data plus control lines.)

        As far as SLIP goes,... interesting idea, very limited in
        packet size since there is only 36 bytes of total ram
        available on the 16C84, kinda makes it hard to buffer 1K
        datagrams.....I could go on but I guess you get the idea..

        I2C is probably a good choice all things considered.