Abysmal Async Performance on MCP Board

[Arch Mott]

Greetings!

We have a Sun 3/160 running SunOS 4.0.3. In the 3/160 we have what used to
be known as an MCP board (Multi-Protocol Comm Processor) and I think is
now known as an ALM-2 (?). The MCP board has 1 of its RS-232 ports running
bisynchronously with Sun's Sunlink BSC/RJE software. The other RS-232 port
is running asynchronously to drive a BDS-1500 line printer. The printer is
set to run at 19,200 Baud.  I have also tried the printer at 9600 baud.
The 2 RS-449 ports are free.

The problem is this:

When sending data to the printer, the number of interrupts being pro-
cessed by the cpu becomes extremely high and system performance degrades
to the point of being virtually unusable. Mouse response is horrible,
anyone logged in to the system experiences terrible response time and the
printer runs at nowhere near it's rated 1500 lines per minute.  The board
performs satisfactorily when just the BSC/RJE is running.  whether or not
BSC/RJE is running, the line printer kills the system.

Does anyone have experience with this set-up (MCP-->Async Printer) ???
Please help if you can. Send your e-mail to: arch at seri.seri.gov

	Thanks in advance,
		Arch.