[net.unix-wizards] Help with LA100 Letterprinter

overlord@spock.UUCP (Rick Link '85 off) (03/25/85)

	I am having some trouble interfacing a DIGITAL Letterprinter
100 to a Vax 11/750 running 4.2bsd UNIX.  I have tried almost every
different combination of switches on the LA100 (XON/XOFF,Modem
Control,Restraint and Speed modes) to no avail.  The printer seems to be
allowing the incomming data to overload its input buffer. It then emits
a series of beeps and prints garbage.  If anyone out there is currently
using a LA100 Letterprinter connected to a similar system as ours, I
would appreciate it if they could send me a letter documenting their
switch settings.

					Thank you,

						Rick Link
						decvax!yale!spock!overlord

gwyn@brl-tgr.ARPA (Doug Gwyn <gwyn>) (03/29/85)

> ...  The printer seems to be
> allowing the incomming data to overload its input buffer. It then emits
> a series of beeps and prints garbage.  ...

I don't think your problem is in switch setting, but rather in the need
to enable DC3/DC! (XOFF/XON) flow control on the terminal port.  This
is done by setting the LITOUT mode and leaving the port in "cooked"
(non-RAW) mode with DECCTLQ set so that flow control is done.