CompuServe Thread

From what I've read, there is a theoretical baud limit in every voice telephone line of about 2400 baud, due to the fact that the typical voice line has a useable bandwidth of 300HZ to 3.3KHZ (about 2400HZ). Which, considering the quality of the average phone line between home and the CO, it's amazing that any modulation can occur! And already there's talk of dial-up 19.2K!

I believe that v.32 9600 bps is 2400 baud (4 bits/baud). I'll look it up.

Don: It's refreshing to see somebody that knows what the terms really mean! Am I correct that a Bell212A modem (or that standard if you like) is only 300 baud/1200bps? A long time ago (well, about 12 years ago) I helped a friend who was customizing the MODEM program (for CP/M) to handle Bell202C modems (1200 baud OR bps half duplex). This was back in the time when a high speed modem (1200bps) was a rarity, and very expensive (if you could even buy one), and we had a pair that we paid $800.00 for (212A's that is). We were doing the work for half duplex, as there were many 202's available at flea markets in the $10.00-$20.00 range. I believe that the 202's are still used by ham operators, as they're about the only modems that have only one carrier tone, only on when sending, quiet when recieving. It's truly amazing the advances that have been made over the last few years, now I have a 9600bps modem that is starting to be considered slow (it can't go higher than 9600!), back 12 years ago, 300 was the norm, and my 'letter quality printer' was a Teletype ASR33 running at the blazing speed of 110 baud! What little programming I still remember (not much) was learned in a HS computer science class that used a PDP11/70 with TTYs as terminals, and PAPER TAPE as the storage media (for students at least). I remember taking those tapes home, and loading them into my NorthStar thru the TTY I had at home, talk about a program taking a long time to load! Sorry for rambling, your message just sort of made me remember to old days (I'm not too sure how 'good' they were) -Mike Schiller In sunny Fort Lauderdale

Aaah! The good old days! The first computer I ever used was the university mainframe – an Elliott 803B. It was the fully expanded version – 8192 words of memory at 39 bits (plus parity) each. The Algol compiler and run-time code took up about 75% of this, and longer programs had to be compiled out onto paper tape. I had the luxury of having two high speed paper tape readers, capable of almost 330 charcters per second (5 bits per character), but running at such a high speed, the readers were prone to making errors, and I remember I had to slug the code somewhat to drop the speed to a still fast 300 chars/sec. The output devices were a pair of high-speed paper tape punches, which zipped long at 100 characters per second. The output tape then had to be wound up and carried next door to a spare Creed teleprinters (there were three in all, for maximum throughput), where the output was printed at a tolerably fast 10 chars/sec. The computer was controlled via a keyboard, about the size of a desk, at which instructions could be entered in machine code. Of course, as with all the best computers, there was also a loudspeaker. The speaker was pulsed every time a jump or floating point math instruction was executed (yes, it even had a math co-processor!), and with a bit of cunning, you could write a program to play a tune. The processor was perhaps a little slow by modern standards – 576 microseconds for most instructions (excluding floating point math), but only 288 microseconds for a jump instruction. Yes, microseconds, not the new-fangled nanoseconds, but bearing in mind that it was a serial processor (i.e. it carried out its instructions on a bit-by-bit basis, not byte-by-byte), this was quite understandable. Ah, the joys of twenty years ago! Shraddhan – via Whap!

Bill– I'm seeing them for $399 at my local CompuAdd store—GVC v.32bis/v.42 9600 baud modem – promises 38,000+ bps. Jonathan Jonathan – from Albany, NY, via whap!

Bill, You have aptly pointed out the difference between an A500-mind like mine, and an A3000-mind like yours! That's what I get for going off the top of my head. Thanks! Tim

John: If you buy a modem with V.32, V.32bis, and MNP 1-5, you should be current for some time. V.32 is the current standard for 9600 with V.32bis the up and coming standard for I believe 14,400. BTW, if you can wait until the first part of January for your modem purchase, then take a look at Supra's soon to be released modems. 9600, V.32, send/receive fax external – street price around $229. 14,400, V.32bis, send/receive fax external – street price around $329. Fax software will probably add a few bucks. I know that Winfax for Windows is $40 and Bitfax is $20, so Amiga software shouldn't be too much. I'm going to buy the 14,400 V.32bis as soon as available. I've had the Supra 2400 for years and never had an ounce of trouble. I like their tech support as well for the few times that I've called them. You can call Supra toll free. Their number is either 1-800-72-SUPRA or 1-800-27-SUPRA. I can't remember which. George