dyer@spdcc.com (Steve Dyer) (05/12/89)
I was travelling on business last month and attepted to use my trusty Toshiba
laptop which comes with a 1200 baud modem. I thought I'd use my AT&T credit
card, since I wanted to avoid the hotel's long distance charges. However,
I found that whenever I dialed direct with the credit card, I would end up
getting an incredibly regular noise pattern: what seemed like <DEL>{ once a
second--you could set your watch with it. This was visible on the screen when
there was no other output, but served to garble any output coming
simultaneously from the host I was connected to.
When I called from the hotel without using a credit card, everything was fine!
Calling the AT&T operator and (hopelessly) explaining my problem, I would
manage to get a clean line about 30% of the time.
What's going on here? I've had this happen now twice, once from Alabama
and once from Tucson. Anyone know of a miniature MNP modem I can attach
to the back of a laptop?
--
Steve Dyer
dyer@ursa-major.spdcc.com aka {ima,harvard,rayssd,linus,m2c}!spdcc!dyer
dyer@arktouros.mit.edujeff@tc.fluke.com (Jeff Stearns) (05/19/89)
In article <telecom-v09i0162m11@vector.dallas.tx.us> Steve Dyer <dyer@ ursa-major.spdcc.com> writes: > I was travelling on business last month and attepted to use my trusty Toshiba > laptop which comes with a 1200 baud modem... Whenever I dialed direct with > the credit card, I would end up getting an incredibly regular noise pattern: > what seemed like <DEL>{ once a >second--you could set your watch with it... Steve, Most phone calls are transmitted as a stream of digital data. (Odd, ain't it; the modem converts digital to analog so the central office can convert it back to digital for transmission...) This digital data stream passes from one network switch to another. The network switches probably aren't synchronized to the same clock. One switch is running slightly faster than the other; thus the digital data stream is constantly and steadily "slipping" as it passes from one to the other. The scrambled bit pattern often contains characters ~ or } or DEL (they're rich in 1-bits). A quick workaround? Route the call along a different path. Using a different LD carrier is very likely to accomplish this. -- Jeff Stearns John Fluke Mfg. Co, Inc. (206) 356-5064 jeff@tc.fluke.COM {uw-beaver,microsoft,sun}!fluke!jeff PS - Calling all users of the Vitalink TransLAN IV Ethernet bridge! Please drop me a line.