Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!mit-eddie!bbn!apple!sun-barr!texsun!texbell!vector!telecom-gateway From: chip@vector.dallas.tx.us (Chip Rosenthal) Newsgroups: comp.dcom.telecom Subject: Re: Modems and LD Carriers Message-ID: Date: 21 May 89 01:53:13 GMT Sender: news@vector.Dallas.TX.US Reply-To: chip@vector.dallas.tx.us Organization: Dallas Semiconductor Lines: 43 Approved: telecom-request@vector.dallas.tx.us X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@vector.dallas.tx.us X-TELECOM-Digest: volume 9, issue 172, message 2 of 6 gould@pilot.njin.net (Brian Jay Gould) writes: >X-TELECOM-Digest: volume 9, issue 160, message 3 of 8 >So... has anyone ever attempted to chart data rate versus carrier? The April 25 issue of |Data Communications| has an article "A quality comparison: Which carrier tests best?" They tested AT&T, MCI, and Sprint with 9600bps V.32 modems (specifically Codex 2264's). They summarized the results of the tests saying: Despite Sprint's new fiber network, AT&T was still the winner in terms of error-free data connections over all links. Not surprisingly, AT&T also won hands down in terms of call-setup time. [...] In terms of signal loss, Sprint was the winner, showing an average receive signal level of -10dBm [...] But when comparing link by link, there was no clear winner. Besides, all the carriers fell well within the acceptable limits for voice. In their tests, they compared: call-setup time, receive-signal level, and bit and block error rate. Their overall summary for connections with data errors (that is at least one error occured during the 1.5 minute BERT with a 511 pattern) was: AT&T ================ 15% SPRINT ==================== 19% MCI ============================== 29% |---------|---------|---------|---------| 0% 10% 20% 30% 40% "Percent of total tested connections with at least one block errored in transmission." However, as others have pointed out, the end-to-end connection is only as good as every link in the chain. -- Chip Rosenthal / chip@vector.Dallas.TX.US / Dallas Semiconductor / 214-450-5337