calway@ecsvax.UUCP (James Calloway) (05/03/85)
x
Several weeks ago I asked for opinions of non-AT&T long distance carriers
for use in transmitting data. Twelve people responded, including three who
simply requested that I post a summary. The responses provided much
information, for which I am grateful. Here is the gist of the information:
Only two people had anything good to say about any non-AT&T carrier. One
had good experiences with MAX, a regional carrier in Michgan. Another
cited TelaMarketing Communications, which is available in North Carolina,
Tennessee and probably other Southern states. TMC is a WATS reseller,
meaning that it resells access to AT&T lines. I suspect that MAX is
also a WATS reseller but do not know for sure.
Two people referred me to Data Communications magazine, which compared eight
long distance carriers for its August 1984 issue. I could not find that
issue, but I talked to John Bush, one of the authors of the article.
He said that all eight carriers were similar in voice transmission
quality, but there were substantial differences in data transmission.
The carriers were tested between the magazine's San Francisco and
New York offices at 1,200 bps. Here are the results of the
bit error rate tests, consisting of 1,200 blocks of 1,000 bits each:
Carrier No. of bad blocks
Allnet 0
AT&T 1
Satellite Bus. Sys. 1.5
Sprint 4.5
West. Un. Metrophone 7.4
MCI 14.4
ITT 72.1
Telesaver 109
I had an interesting conversation with David Anthony of DataSpan in Charlotte.
His firm makes devices that transmit digitized medical photographs
at 9,600 bps, a speed that appears to separate the wheat from the chaff
rather decisively. He simply laughed when asked about non-AT&T lines.
He said he had modest success with TMC and Allnet. Sprint and MCI wouldn't
work at all at 9,600 bps, he said.
I contacted the six carriers in my area (Raleigh, N.C.) that have signed up
for equal access. All said their lines could support at least 1,200 bps,
except SouthernNet, which claimed 4,800 bps and TMC, whose spokesman never
seemed to understand what I was asking.
Other points raised:
Billing - Sprint starts charging after the first 30 seconds and MCI
after the first 48 seconds, regardless of whether the other party
answers. An MCI spokesman said the company would stick to that
policy, but Sprint plans to switch under equal access to the
same method used by AT&T and other carriers I contacted, namely
to charge only from the time the other party answers.
Satellites - As I understand it, satellite links offer a trade-off
between better quality connection and problems caused by the
time lag. If you are using an older protocol such as XMODEM,
a satellite link can greatly slow file transfer.
Bell, ITT and MCI say they are tryining to reduce their usage. ITT and
MCI claimed less than five percent. Sprint, on the other hand, is
increasing satellite usage to as much as 15 percent by the end of
the year.
Support - As several people pointed out, it often is difficult to find
people at any carrier who understands data transmission, even though
they are bound to be there somewhere. Anthony said that once he
found the "data transmission guru" at a phone company, he
could get the info he needed. He actually was referring to local
phone companies, which is the last point.
Local service - Anthony said his biggest problems were with local phone
companies, especially "mom and pop" phone companies using old
switching equipment. Quality of local service appears to vary as
much or more than long distance service.
--
James Calloway
The News and Observer
Box 191
Raleigh, N.C. 27602
(919) 829-4570
{akgua,decvax}!mcnc!ecsvax!calwaylauren@vortex.UUCP (Lauren Weinstein) (05/05/85)
By the way, when a company claims they will be switching to answering-based billing "under equal access," this means after equal access goes in ON THE DESTINATION END OF THE CALL. Whether or not you have equal access on the originating end of the call is unrelated to the issue. Since many, many communities will never be equal access (only communities over a certain size will necessarily be covered) even those non-AT&T carriers who WANT to bill "properly" may not be doing so to many areas. Also, those same companies are only starting the process of setting up equipment to process answering supervision data, even when destination equal access is already in place. And as someone else already pointed out, many of the alternate carriers don't intend to bill via any means other than timing (no supervision) in any case. This causes major problems with automated modem calls, as you might expect. Regarding the "Data Communications" survey--I've never put much faith in surveys that only considered a single (or only a few) paths. Their survey was between only two points (and major metro areas at that) so they didn't get hit too badly with one of the alternate carriers' worst problems--variability of trunk quality from route to route. Still, it appears that the general consensus is that the alternates are risky, to say the least, when it comes to data. Which is about the outcome I would expect. --Lauren--