UARTs, serial ports and 28.8 modems...problems!

UARTs, serial ports and 28.8 modems...problems!

Post by ENVS » Wed, 14 Feb 1996 04:00:00

I just upgraded to a USRob. 28.8 Sportster (from a 9600 ick!).
I have been having problems dialing in every now and again, and worse, it
when I running Netscape and the line disconnects, it seems to lock my

Anyway, my machine is a gateway 486 66, 20mb ram, 1.2.8kernel.
With the 9600 modem, the SLIP connection worked fine, I didn't change the
vanilla rc.serial, and used a stock dip script. With the 28.8 I have to
try sveral
times for a connect, and I get disconnected alot. All the autoconfig AND
manual config is commented out in my rc.local, apart from 2 lines near the
beginning which perhaps are basci auto config lines?

I tried MSD in DOS, and it told me my UART chips are 8250 (serial rate
Should I comment out those first two mystery  lines in my rc.serial and
${SETSERIAL} /dev/cua1 uart 8250 port 0x2F8 irq 3
Will my mouse still work???
Do I need to change anything on the modem, as I understand it has a 16550



UARTs, serial ports and 28.8 modems...problems!

Post by Thomas Wischgo » Sun, 18 Feb 1996 04:00:00



Quote:>I tried MSD in DOS, and it told me my UART chips are 8250 (serial rate

This could be the problem. For a 28.8 Modem you need a serial card with a
16550 UART chip, which buffers the data, so the computer does not need to
to get the data bit by bit. Perhaps because of the missing buffer you lose
data and then you get disconnected. So buy a new serial card if you want
to use the Sportster and then set the port speed to 115200b/s.
Quote:>Will my mouse still work???

You can set the port speed for any serial line independently, so your mouse
will still work because it's on an other line (/dev/cua0 I guess).
Quote:>Do I need to change anything on the modem, as I understand it has a 16550

Normally not.



           "He who isn't feeling confused must be disinformed"


1. Problem with 16550A high speed serial port and 28.8 modem

Hi I have a 28.8 modem that I was using a 16450 uart.  Everything worked
fine, but I decided to get a faster serial card with 16550A uarts.

I got everything hooked up ok and I can dial out and connect with ppp
but when I start anything that transfers a lot of data the connection
stops totally untill I hangup and redial.

I used setserial to specify the spd_vhi flag, and it detects the right uart.
What is causing this.  With ftp it will hang within 10 seconds.  Going
back to the old serial port everything is fine again??

I am running kernel version 1.3.45 ppp 2.2.0c


Ps I run the 16540 uarts with the spd_vhi also and it connects at a high
rate with very few errors.

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