[SunRescue] Serial ports and MODEMs

Gregory Leblanc GLeblanc at cu-portland.edu
Thu Mar 30 12:06:36 CST 2000


> -----Original Message-----
> From: Chris Powell [mailto:Chris_Powell at mitel.com]
> Sent: Thursday, March 30, 2000 5:00 AM
> To: rescue at sunhelp.org
> Subject: [SunRescue] Serial ports and MODEMs
> 
> All,
> 
> What are people managing to squeeze through the serial ports of their
> Suns? I'm using a 14.4k MODEM (!) through my IPC to connect to an
> ISP (hey, acronym overload!). This works fine, but is rather slow.
> The serial port on the IPC is set to 19200. I understand the tiny
> buffer of the serial ports (4 bytes or something?) precludes the
> theoretical maximum of 38400 baud. Does anyone use this rate reliably?

I'm fortunate enough that I don't believe in modems anymore (DSL rocks), but
I think that you should be able to use 38400 on that machine pretty
reliably, as long as the processor isn't too busy (like Seti at Home or
something).

> If I invest in a faster MODEM (56k), will I be wasting my time as the
> serial link becomes a bottle-neck? What about later sun4m machines
> such as the Classic, SS5, SS10? Do they have better serial 
> controllers?

I don't think the serial port "issue" was resolved until the advent of
Ultras, and I'm not even sure if the early Ultras had good serial ports.
Who needs serial when you've got a network, right?  If you disable
compression on the modem, and use software compression with your PPP
program, you should be able to get 38400 out of the serial port at least.
If you let the modem do compression it will be a waste, because the serial
port could become the bottlenect on text pages easily.
	Greg





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