135 lines
6.0 KiB
Prolog
135 lines
6.0 KiB
Prolog
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#2 33 07 Aug 85 06:32:49 $0.00
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From: Donald Larson on Fido #333 in Net #115 Attache_Node, Schaumburg...........IL
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To: Sysop And All On on Fido #100 in Net #115
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Subject: Long Distance Services
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Everyone has asked at one time or another which of the long distance services
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are the best for data transmission. This is especially true for the person
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who calls all over the country in search of that one program that will make
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their life easier. Here's the story, according to an article in the August,
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1984 issue of Data Communications.
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The editors of the magazine made the following tests and observations.
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Carrier Connect Attempts 1st Try BER Error BLER Signal
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Time Required Burst Loss
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Allnet 17.86 1.07 93 0 0 0.0 -21.5
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AT&T 14.16 1.07 93 105 0.99 1.0 -18.7
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ITT-USTS 19.68 2.93 40 2535 9.02 72.1 -20.6
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MCI 14.96 1.27 73 427 1.82 14.4 -24.2
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SBS 21.72 1.13 87 64 0.50 1.5 -18.9
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SPRINT 16.40 1.67 56 96 0.50 4.5 -18.3
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TELESAVER 26.67 1.40 80 4314 23.3 109.0 -19.5
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WU 19.78 2.60 47 221 1.64 7.4 -24.8
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Connect Time - Seconds from last digit to answerback from distant modem
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Attempts - Average Number of calls required to complete call to other end
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1st Try - Percent of calls completed on first try
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BER - Bit error rate, number of bits in error per million bits
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Error Burst - number of bursts where 80 consecutive bits in error per million
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bits transmitted
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BLER - Block error rate, number of 1,000 bit blocks per 1,000 blocks
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Signal loss - loss of signal level (in db) at mid frequency (1004 hz)
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This is installment 1 of 3 installments. More later.
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Don
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Read Command [2] 1 - 26, * :
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#3 30 07 Aug 85 21:39:21 $0.00
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From: Donald Larson on Fido #333 in Net #115 Attache_Node, Schaumburg...........IL
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To: Sysop And All on Fido #100 in Net #115
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Subject: Long Distance Services (Part 2)
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OK folks, here's installment 2 on long distance services for data
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transmission. Again, this information is from an article in Data
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Communications, August 1984. Here are some additional pieces of data:
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Carrier Slope S/N P/AR Jitter Billing
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Allnet 5.4 27.8 57.5 5.8 8.4 $3.52
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AT&T 1.7 31.0 71.3 4.5 9.0 $5.06
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ITT-USTS 6.3 25.4 55.3 10.0 9.0 $3.95
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MCI 7.8 27.9 58.4 6.7 10.0 $4.31
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SBS 5.6 30.4 50.0 4.1 9.4 $3.67
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SPRINT 7.4 28.7 63.6 6.1 10.0 $5.10
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TELESAVER 7.3 26.1 41.9 8.5 11.0 $4.91
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WU 8.6 29.0 62.8 5.5 11.0 $4.73
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Slope - Difference in attenuation (or loss) between middle frequency (1004)
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and the high and low levels (averaged). (Bell Spec < 14)
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S/N (Signal to Noise) - Measurement of signal strength over noise (static)
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background. (Bell Spec > 24 db)
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PAR (Peak to Average Ratio) - Measurement of velocity distortion according to
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frequency. Medium speed spec from Bell is > 48.
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Jitter (Phase Jitter) - Measurement of AC influence upon signals, measured in
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degrees. Maximum permitted by Bell is 10 degrees. Especially rough on phase
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modulated modems (212A is Phase shift keyed).
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Billing - Actual time was 8.5 minutes. Amount shown is the amount the carrier
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billed. This may be due to billing errors and/or minimum connect times
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(particularly important for Fido's short connects). Dollar amounts are for
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coast to coast tests and may not be accurate for other comparisons.
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In the next and final installment, I'll discuss these stats in a management
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overview style (excerpted from the article and annotated by my experience)
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along with personal observations.
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Stay tuned for chapter 3 (Summary and Recommendations along with a discussion
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of equal access and the national toll network).
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Don
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Read Command [3] 1 - 26, * : 3 4
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#5 37 13 Aug 85 16:18:05 $0.00
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From: Donald Larson on Fido #333 in Net #115 Attache_Node, Schaumburg...........IL
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To: Sysop And All on Fido #100 in Net #115
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Subject: Long Distance Services - Part 3
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This is the executive summary of the previous two articles.
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Allnet - Best cost and bit error rates. Suffered slightly in analog line
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measurements. Data applications are highly ranked but the voice levels may
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suffer. Excellent prices and billing accuracy.
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AT&T - Best overall quality for mixed voice and data applications. In general,
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the rates they charge are not bad for the quality compared to the batting
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averages, rate accuracy, etc. Still the standard to compare against.
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GTE Sprint - Good quality for data, less for voice. The general call "batting
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average" for first try call completion. Ended up as the highest call cost on
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timed calls. Their actual rates are lower than AT&T but the billing accuracy
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was poor.
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ITT USTS - Poor by almost all standards, except for price. Recommended for
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patient voice callers with plenty of time.
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MCI - Mediocre for data. Voice quality probably acceptable but data
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performance not as good as others available.
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SBS - Second best in savings and surprisingly good quality. A little long in
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call set up time. May be some problems with over 1200 bps data due to
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relatively poor P/AR rating. Heavily recommended by Data Communications's
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magazine tests.
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Telesaver - Worst bit and block error rates overall. Minimal savings over
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AT&T does not justify for data or even voice.
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Western Union - Poor call completion first attempt average; often required
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more than six attempts to connect. Passable data performance but marginally.
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Not recommended for short voice and data calls but savings may be worth it on
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long length rates.
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I personally have been using SBS for several months with a great deal of
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success. I highly recommend it. I have also used MCI but had a greater
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problem with error rates. My best advice is to try out the carrier and see
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what you see.
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Don
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PS - Let me know your experiences; I'll try to collect them and publish them
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occasionally.
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