Here's my requirements:
* 56k DOV only - DOV is unmetered, and data channels are metered and more
expensive. Know your tariff.
* Both channels in use to get more than 56k.
* Linux use
* Compatibility with Livingston PM2i/5BRI access server which I own on the
other end.
Getting 56K DOV working was easy. It works just like a modem in linux. Log
in with either PAP or scripted chat login.
To make it DOV, set the appropriate S-register, or use the win95 utility
to do it on another computer. Tollmizer, 3com calls it.
Be sure your livingston (or your ISP's livingston has ISDN provisioned to
support voice). The livingston produces an audible tone which is used when
setting up the call to make it a "voice" call, but it is a perfectly good
100% digital end-to-end connection which works at exactly 56k. Not all
ISDN equipment supports reception of DOV calls; check this first.
I know livingston supported multiple B-channels per connection, and
verified with them that it would support multiple DOV B-channels. It does.
The 3com needed to be upgraded from v3 to v3.1 to support multiple DOV
B-channels. I already knew this from helping a win95 ISDN customer.
Getting both channels working at 56k DOV was another problem.
on the 3com, I ended up setting s71=1. This disabled v120, which is not
conducive to multiple B channels. This setting is for Async-Sync PPP
conversion. It was hooking me up with v.120 every time before. I also
turned off CHAP on the 3com s84=0, it should be anyways, but I wanted to
be sure. Also s80=1 enables Multilink PPP.
You must also log in with PAP and not a scripted username/password
process.
Dialing format is atdnumber1&number2
We ordered our lines with no data service. (Voice only) Not only is this
cheaper per month, as each data channel costs $, since voice is unmetered,
we don't have to worry about the possibility of losing some S register
setting (acidentally) and running up a 2 cent/minute == $30/day ==
$900/month phone bill for data services. This really does happen, but not
to us.
Since it's an Async connection from the view of our computer, we get about
10-11 KBPS throughput. Latency is about 50ms. If we were using an office
router or other solution with no async-sync conversion, throughput would
probably be more like 12 KBPS (56k*2) and latency somewhat lower (30-50ms
range?)
If this were an integral part of a large multihop network I'd go for the
lower latency solution. For this application (light interactive use
(keyboard activity) and small amounts of web browsing for an office of 6
geeks), I am quite pleased with the results.
-- /* Jason Philbrook | Midcoast Internet Solutions jp@midcoast.com | Internet Access, LAN, WAN, and Linux www.midcoast.com/jp/ | Service and Consulting for Midcoast Maine */- To unsubscribe, email 'majordomo@livingston.com' with 'unsubscribe portmaster-users' in the body of the message.