Equinox hardware flow control

[Chris Lewis]

In article <1991Feb19.153604.13096 at gwinnett.UUCP> todd at gwinnett.UUCP (Todd Reese) writes:
>Trailblazers do not need flow control when using UUCP.  The modem has
>UUCP -g protocol built in.  This is what makes it able to produce output
>with PEP mode of 19200 baud. At a lower link speed (e.g. 2400 baud) the
>UUCP from the host computer to the remote is handled directly.

Trailblazers *do* need to use flow control in most UUCP situations.  One situation
is where the modem is transmitting to "their" host, and the host can't
quite keep up to bursts.  If the host doesn't flow control, it'll lose characters.
This can often be bad enough to drop connections even with UUCP packetizing
and retransmissions of packets after errors.  (eg: if, from a quiescent state,
your host will frequently drop a character from a continuous 19200 baud input
burst, you're toast)

Even if the speed mismatches aren't bad enough to drop connections, the
packet retry rate can be sufficiently high to seriously degrade your
throughput.

Further, you can't use x-on/x-off flow control on a UUCP connection, because
x-on and x-off are part of the UUCP protocol.  Thus, hardware handshaking
is recommended to ensure that no characters are lost, and that as long as
the host can keep up, on average, with the modem, you'll get the highest
possible throughput.
-- 
Chris Lewis, Phone: (613) 832-0541, Internet: clewis at ferret.ocunix.on.ca
UUCP: uunet!mitel!cunews!latour!ecicrl!clewis; Ferret Mailing List:
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