Re: Phone lines

[CUTjefbla@bconnex.net (Jeff Blakeney)]

On Sat, 03 Mar 2001 08:12:13 GMT, "Simon Biber"
<simon@basilisk2.cjb.net> wrote:

>OT: I wonder if it is possible to control the ports in that way on an early
>Mac ? I'd like to be able to connect my null-modem to the PC at 115200 bps
>instead of 19200 bps

The serial ports in the IIgs, and almost certainly the Mac as well,
are limited to a maximum of 57,600 bps when doing asynchronous
communications.  They can only achieve faster rates, including the
230,400 bps maximum, in synchronous mode.

RS-232 is an asynchronous standard and cannot be directly connected to
a synchronous system.

AppleTalk on the IIgs uses the synchronous mode of the serial ports
when connecting over a LocalTalk network giving a theoretical maximum
transfer rate of 230,400 bps.  However, there is a lot of extra work
that the IIgs has to do to deal with this type and speed of connection
which is why it uses an interrupt driven system and tends to slow down
the machine a bit.

--
 Jeff Blakeney - Dean of the Apple II Unversity on A2Central.com