Re: USR 5610

Stephen Kirkpatrick wrote:
> I have an internal US Robotics/3Com 56K FaxModem Model 5610 (rev 1) and 
> did not have any problems with Linux (RH 7.3) recognizing the device.  I 
> am using the modem for a ppp server and have never had good performance 
> from the modem.  I am getting connections of 9600bps.  I was wondering 
> if anyone has used this modem for a ppp server and if they have 
> experienced performance issues too.
> 
> I can pretty much rule out the telephone lines since I have used a 
> number of internal IBM modems with respectable performance (around 
> 24000bps).  I assume the performance is a configuration issue, but all 
> of my google'ing has yet to produce a solution that actually improves 
> performance.
> 
I am using "an internal US Robotics/3Com 56K FaxModem Model 5610"B PCI 
MODEM, "56K Performance Pro Modem" Serial #23PBGBEC02PK in my home-brew 
computer. It is plugged into Slot 1 of PCI-X Bus 1, coming in as 
/dev/ttyS4 using IRQ 104 (not a typo). It works just fine and sometimes 
hits transfer rates well over 6000 bytes/second. Of course, sometimes it 
goes down to 104 bytes/second or stops, but I tend to blame that on the 
servers or a clogged Internet. I am running it on RHEL 3 ES, in case that 
matters to anyone.

Now my telephone lines are pretty bad. I have one that I use voice only 
and one that I use computer only. Sometimes they work harmoniously, and 
sometimes the crosstalk from one phone line to the other is so bad I can 
hardly hear the person at the other end of the line over the modem signal, 
and the voice connection can cause the data connection to hang up. But I 
cannot really blame the modem for that. That does not happen all the time, 
but it is frequent.

So, to me, you are getting poor performance even with those IBM modems. I 
do not consider 24000bps to be good performance at all. I sometimes get 
12K bytes/second, though that is atypical. 6K/second is usual on good 
days, and 3K to 4.5K is usual on average days. Bad days are almost unuseable.

-- 
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