[comp.sys.hp] 9000/345 RS232 speeds?

tt@euler.jyu.fi (Tapani Tarvainen) (05/21/91)

Does anyone know how high speeds the built-in RS232 interface fo a
HP9000/345 can handle?  At least it seems to work at 38400 baud;
can it do more?  What magic incantations would it take?
(stty won't set speeds higher than 38.4k, and kermit's limit seems to
be 19200 :-( )
What about a 425?
--
Tapani Tarvainen    (tarvaine@jyu.fi, tarvainen@finjyu.bitnet)

rjn@hpfcso.FC.HP.COM (Bob Niland) (05/24/91)

re: > tt@euler.jyu.fi (Tapani Tarvainen) writes... >

> Does anyone know how high speeds the built-in RS232 interface fo a
> HP9000/345 can handle?  At least it seems to work at 38400 baud; can it do
> more?  What magic incantations would it take?  (stty won't set speeds
> higher than 38.4k, and kermit's limit seems to be 19200 :-( )

With the 7.05 driver, speeds up to ~400K may be declared, a 16-byte FIFO is
enabled, and CTS/RTS hardware flow control is available.  For 7.0 and 7.03,
you need a patch shar, available from me via your local HP support person.
Have them contact me if they don't have a copy.  The shar is also useful for
documentation at 7.05.

> What about a 425?

The higher speeds, FIFO and CTS/RTS flow control apply to the first (select
code 9) serial port on all Model 400 machines including 425t, but excluding
the new 425e.  This type port, based on the Ns16550, has not been fully
characterized at high speeds on a busy system.

The other two ports (select codes 5 & 6) have the characteristics of the
older Apollo DN-series ports; the 425e has only this type of port.  Although
this port has some buffer, it lacks CTS/RTS and has a fairly low max bps
rate (perhaps 38,400).  I have no further data on it.

Regards,                                              Hewlett-Packard
Bob Niland      Internet: rjn@FC.HP.COM               3404 East Harmony Road
                UUCP: [hplabs|hpfcse]!hpfcrjn!rjn     Ft Collins CO 80525-9599