craig@bandw.uunet (Craig Goss) (01/24/91)
Is anyone familiar with a standard method for measuring fax transmission times. I have seen advertisements from several manufacturers of fax machines that claim a "x second" transmission time. My guess is that one of the CCITT test documents is used to determine the number of seconds for a single page, but I have seen nothing which details the reqirements for such testing. Is there some science to these claims or are these figures just a pipe dream. Thanks, Craig -- -------------------------------------------------------------------- Craig Goss UUCP: uunet!bandw!craig B&W Software Moretown, VT --------------------------------------------------------------------
cafl@lindy.stanford.edu (Carol Farlow Lerche) (01/24/91)
Our Okidata FAX machine footnotes CCITT test document #1 in its data sheet claiming 10 sec/page, and 15 pg storage (modified READ, 9600 bps).
jon_sree@world.std.com (Jon Sreekanth) (01/24/91)
In article <20602@know.pws.bull.com> eli@pws.bull.com (Steve Elias) writes: In article <1991Jan23.223517.531@uunet!bandw> craig@bandw.uunet (Craig Goss) writes: >manufacturers of fax machines that claim a "x second" >transmission time. lies, damned lies, and benchmarks. :) Many times, these optimistic speeds are quoted for transmission between models from the same manufacturer, where the units transact some proprietary compression mode. My Sharp FO 215 says in the user manual, "Approx transmission time, 15 sec, in Sharp special mode. Based on CCITT test chart #1 at standard resolution in Sharp special mode, excluding time for protocol signals i.e. CCITT phase C only" For true numbers, IMHO, magazine reviewers are more realistic, since they'll give a time measurement for the whole process, from picking up the phone to hanging up. This is really what one is interested in, rather than just the document transmission phase. In actual use, my machine is certainly under a minute for 1 page transmissions, but when used in halftone mode, with a postcard sized photograph, it's about 90 - 120 seconds. Regards, / Jon Sreekanth Assabet Valley Microsystems Fax and PC products 346 Lincoln St #722, Marlboro, MA 01752 508-562-0722 jon_sree@world.std.com
Barry Schoenfelner - bas@chem.wayne.edu (01/25/91)
In article <JON_SREE.91Jan24102928@world.std.com> jon_sree@world.std.com (Jon Sreekanth) writes: >For true numbers, IMHO, magazine reviewers are more realistic, since >they'll give a time measurement for the whole process, from picking >up the phone to hanging up. This is really what one is interested in, >rather than just the document transmission phase. I am new to this so could someone fill me in on what magazines review fax machines? My wife wants to start a DTP/secretarial service from the house and would like to get a fax. Any tips would be greatly appreciated. Barry Schoenfelner bas@chem.wayne.edu
mikes@gammafax.gammalink.com (mike spann) (01/26/91)
In article <1991Jan23.223517.531@uunet!bandw> craig@bandw.uunet (Craig Goss) writes: >Is anyone familiar with a standard method for measuring fax >transmission times. I have seen advertisements from several >manufacturers of fax machines that claim a "x second" >transmission time. Their ain't no such thing. >My guess is that one of the CCITT test documents is used >to determine the number of seconds for a single page, but >I have seen nothing which details the reqirements for such >testing. Is there some science to these claims or are these >figures just a pipe dream. The numbers they quote are much like the numbers quoted in benchmarks. They are not quite lies, but they often indicate values that are rarely acheived in real life. (We have all heard about MIPS and SMIPS..) The time necessary to send a page of facsimile data is dependant on several factors including (but not limited to): the content of the image, the data rate, the compression algorighm and the minimum scan line timing imposed by the receiver. A manufacturer will often play with all four factors to achieve very fast times. They will pick an image that compresses very well, they will use a proprietary modulation technique, they will use a proprietary compression technique and they will eliminate minimum scan line timings. Needless to say, these 'NON-CCITT' parameters will not work with any machine OTHER than another BRAND-X machine, although the BRAND-X machines will default to CCITT conformance when dealing with other machines. This is why you will often see the disclaimer (in tiny print) that the timings are only to another BRAND-X machine. Going to another machine will achieve slower transmissions. This is not to say that these overly optimistic numbers are bad things to look at. A branch office that only sends faxes to the main office, or the reciprocol operation, SHOULD look for a single vendor of fax machines that have nice proprietary features. This will reduce operating costs for the majority of your traffic. The performance to out-of-house sites will be no worse than with any other fax machine. BTW: the RECEIVING fax machine has the final say on how fast, what compression and what scan line timing to use. Like they say, a chain is only as strong as the weakest link. Having the fastest, most expensive fax machine in the world won't speed things up when you try to send to an 'oldy-moldy' machine that someone else has. mike -- Michael Spann mikes@gammalink.com Voice: +1-408-744-1430 Fax: +1-408-744-1549 UUCP: ...!uunet!gammafax!mikes CIS: 73747,441
bill@camco.Celestial.COM (Bill Campbell) (01/26/91)
Using the UNIFAX software with an Extern Everex Class II modem my
normal time for two pages (cover sheet and one page) from connect
to finish averages about 70 seconds. I'd have to go back through
my log files to get it exactly, but I have noticed that it is JUST
over a minute (since I figured phone charges are fixed for the
first minute).
This is using the standard resolution. I haven't timed it using fine.
Bill Campbell
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INTERNET: bill@Celestial.COM Bill Campbell; Celestial Software
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