Re: Apple II C start-up disc.

[pubpc1@library.ucla.edu]

Andrew Roughan <posty@203.triode.net.au> wrote:
>
>Randy Shackelford <shack@deimos.frii.com> wrote:
>> >BJ, unless a //c has the earliest motherboard, which has a timing
>> >defect, the port can drive a 14.4Kbaud modem fine.  You can also
>> >hook up a faster than 14.4 modem, but the port speed is limited
>> >to 19200, so you don't gain anything.
>
>> Since //c's have no flow control, and the port goes from 9600 to 19200, 
>> there is no way to run a 14400 at higher than 9600.
>
>That's not strictly correct. Hopefully this will elaborate on the situation:
>
>If you have a //c which runs fast enough, then you should lose no characters
>while the port is running at 19.2k, however, in practice, the standard //c 
>will not keep up sufficiently at this speed.
>
>There are no pins available for * Hardware * flow control, however the //c
>can use XON/XOFF flow control with software which supports it. This may
>allow a //c to keep up with 19.2k while you are not making heavy use
>of the downlink....
>
>However in practice for a reliable session you'd probably set the port speed
>to 9600. The modem may try and negotiate 14.4k with the other side
>but if it does you'll soon blow the modems internal buffer and lose
>characters or even lose your connection with any kind of modem error
>checking enabled.
>
>Therefore you'll want to limit your 14.4k modem to 9600.

Well, on a Laser 128EX or EX/2 computer, which runs a 3X the
//c and uses the same modem cable as the //c, 14.4k works fine.

However, even if it is true that a standard //c without a ZipChip
is practically limited to 9600, 9600 is still four times faster
than 2400.

None of this applies to the IIc+, of course, which is more than
fast enough to do 14.4k and uses the same cable as the GS/Mac.

-Scott G.