Keith Petersen <W8SDZ@SIMTEL20.ARPA> (12/20/84)
This is file 2400BAUD.TXT - relayed from the RCPM circuit:
--Keith
From: Wayne Masters, Potpourri sysop
(408) 378-7474 300/1200/2400 baud
San Jose, Ca.
Subject: New 2400 baud modems 8/19/84
Many of you have asked technical questions about the 2400 baud
modems now on the market (and more being introduced monthly). As most
of you know by now Irv Hoff and I have been beta testing 2400 baud for
several months. The test results are amazing to say the least. Running
controlled tests on standard dial-up phone lines with random "noisy
connections", the number of "hits" on a given file transfer is less by
a factor of 10 using 2400 baud vs 1200 baud. So it is concluded that
2400 baud technology is working and will soon be available on most
commercial and private dial-up systems. Now, what is a "standard" 2400
baud modem?
You will no doubt see various technical descriptions of a given
2400 baud modem touting it's features. Be sure the modem you choose has
this specification:
CCITT recommendation for a V.22 bis modem communicating at 2400 bps.
Further explanation of this CCITT standard:
Frequency- Bell 212A
Encoding modulation- 16 level psk (quadrature AM or QAM)
This sounds a lot like the Bell 212A standard for 1200 baud--and it
is. The difference is in the encoding or modulation scheme. Bell 212A 1200
baud uses 4 level psk and 2400 baud uses 16 level psk. If you "listen" to
the 2400 baud carrier it will sound exactly like the familiar 1200/212A-
like "static" or a scratchy noise.
Features to look for in your search for the "right" 2400 baud modem:
1. Does it retain 300 baud bell 103 capability? (most offer 1200 baud as
a "fallback")
2. Is it "smart"--a biggy if you intend to call other systems a lot.
3. Does it offer autoanswer--a biggy if you run a remote system.
4. Price--a real biggy
So far, none of the modems on the market offer all these features
in a "standalone" modem. That is one big reason why Irv Hoff and I have
been involved with Racal-Vadic--not only beta testing to prove 2400 baud
technology...but to get the features most users prefer designed into the
modem. Others may follow some day but Racal Vadic will introduce their
"standalone" modem in time for Christmas 84 with the following features:
1. Smart-autodialing. It will recognize both the Hayes and Vadic commands.
2. 0-300 baud at both Bell 103 and Vadic protocols
3. 1200 baud at both Bell 212A and Vadic protocols
4. 2400 baud CCITT V.22 bis
5. Price is expected to be $695.00 retail
The first release will be an external RS-232 model. Early 1985 will
see the single card slot version for IBM PC's and compatiables.
In order for 2400 baud to be in "great demand" there must be systems
available for the users to access. I am working with Racal-Vadic to
identify RCP/M and RBBS systems where 2400 baud modems could be placed to
generate public interest in 2400 baud. Sysop's should contact Potpourri
at 408-378-7474 if interested in participating.
Now about software to support 2400 baud.
Both MDM7 and MEX will support 2400 baud if the user modifies his
port overlay to setup his port for 2400 baud.
For sysops who use BYE3, the problem is different. Most
implementations of BYE rely on the hardware's Data Available signal (DAV)
to trigger a check-for-carriage-return sequence at different baud rates.
If most hardware is like mine (Z80 SIO), if the hardware is set to look
at 300 baud and the modem answers at 2400 baud the DAV is never set and
you are in an endless loop. Same thing happens if you set the hardware
to 2400 and the modem answers at 300.
I modified BYE3 (version 26 and up) to handle TSTBAUD differently.
I chose to look at each baud rate in 2 second windows, 300 first, then
1200 and 2400, and loop thru this sequence until a C/R or L/F is detected.
The caller is never more than 4 seconds away from his calling speed but
must continue to issue c/r's until the familiar message "Nulls, if needed"
is displayed. Sysop's who choose to use BYE3 need only add the "SET2400"
code into their port insert.
Well, enough for now. Feel free to contact me if you are more
confused now than you were before reading this.
-wayne masters, Potpourri sysop-
408-378-7474bruce%cmcl2.uucp@Seismo.ARPA (12/27/84)
For those of you in the market to buy 2400 baud modems I want to
inform you of a great deal. I would like to state that I am not
affiliated with ANY of these companies, and I am not receiving and
benefits by posting this information!
After spending a few days pricing modems I have compiled the following
information (saving the best for last). If anyone has any additional
information I would greatly appreciate it.
We were interested in rack mounting them so most of the prices given
are for cards that would plug into a rack. "box" refers to a stand
alone modem.
DEC 1 - (800) 962 - 3244
now DF112-AM 300/1200 card $ 506
now DF126-AM 2400 only card $ 634
Racal Vadic 1 - (800) 482 - 3427
now VA212PAR 300/1200 card $ 445
3/85 VA4224 1200/2400 card $ 740
now VA1681 houses 16 rack $ not priced yet
Concord Data Systems (617) 890 - 1394
Q10-24
now CDS224 AA/ORG 1200/2400 box/card$ 845 $ 825
now CDS224 Autodial 1200/2400 " $ 995 $ 975
now CDS224 ARQ 1200/2400 " $1295
now CDS224 ARQ Auto 1200/2400 " $1395
now CDS224 Super 1200/2400 " $1695
now CDSRM-07A houses 7 rack $ 750
Hayes 1 - (800) 241 - 6492
now Hayes1200 300/1200 box/card$ 499
2/85 Hayes2400 300/1200/2400 box/card$ none
now 08-00056 houses 6 rack $ 766
Quantity Discounts are minimal.
Micom 1 - (800) 527 - 0204
Q >16
now M3012 300/1200 box $ 495
now M3012 plus 300/1200 box $ 595
1/85 M3024 1200/2400 box $ 795
1/85 M3024 plus 1200/2400 box $ 895 $ 805
" " " card $ 845 $ 760
now M3200 houses 16 rack $ 750
General Datacomm (203) 574 - 1118
Q 10 - 19
now DC211AL 300/1200 box $ 675 $ 595
" " " card $ 585 $ 520
1/85 DC2412 1200/2400 box $1195 $1050
" " " card $1105 $ 790
" DS1 houses 16 rack $ 795
Paradyne 1 - (800) 482 - 3333 or 1 - (800) 342 - 3532
now DTU1200D 300/1200 $
now 1200/2400 $ 900
NEC 1 - (800) 538 - 8166
Q 11 -20
now N212BRL 300/1200 box $ 795 $ 669
" " " card $ 725 $ 606
" DSP2430 1200/2400 box $1095 $ 976
" " " card $ 965 $ 855
" N4083 houses 8 - 1200 rack $ 625
" SR0801 houses 8 - 2400 rack $ 900
QUADRAM (404) 923 - 6666
Q > 3
now QM10000 300/1200 $ 695 $ 625
not available ?/2400 $
NO Rack mounting.
Ven-Tel 1 - (800) 538 - 5121
Will Call me back.
300/1200 $
?/2400 $
Promethus (415) 490 - 2370 (check 800)
Distributor:
Will call me back.
300/1200 $
?/2400 $
Fujitsu (408) 946 - 8777 ext 576
not available 300/1200 $
now F1935B 1200/2400 $ 895
-------------------------------
CTS Datacomm (203) 743 - 3681 Pete Coccaro
Distributor: Professional Network Services
Harvey Schlesinger (617) 449 - 6460
Model: CTS2424AD
These people had by far the best deal.
The list price for the Stand Alone (box) modem is $ 795
The list price for the (rack) mounted modem is ~$ 700.
Besides starting off $ 200 less than everyone else their
quantity discounts are very good. The Stand Alone modem
will be available starting January, and their rack mount
modem should be available February.
Here is a Quantity discount price list.
Quantity %dicount S.A. rack
======== ======== ==== ====
1 list $795 $700
2-5 10 % 716 630
6-10 20 % 636 560
11-25 25 % 596 525
25- 30 % 556 490
For all of you usenet sites that are still running 1200
(or possibly even 300) the modems will pay for themselves
very quickly.
From all of the literature that I have recieved here are
a few of the advantages of this modem above the others:
1) works at 300 or 1200 or 2400 asyn (others only 1200/2400)
1200 or 2400 sync
2) Stores 10 numbers (40 chars each) (others only 1)
3) For tone dialing it dials ALL 12 (others only can generate
tones including (* and #) numbers 0-9)
This last one caused a nasty problem when we needed to
generate the extra tones because some of the sites we talk to
have switching systems that require them (Gandalf).
4) Will automatically change the speed (some of the others needed
to the other modem. a manual intervention).
---------------
usenet: {philabs, allegra}!sbcs!bruce Bruce Factormdg@ariel.UUCP (M.GALE) (12/28/84)
Please note at the beginning that this is coming from an account on an AT&T computer. <Reach out and byte someone...> Just wanted to point out that in the recent summeries of modems available people seem to be missing a major manufacturer of modems -- A T & T. Check it out with an A T & T - I S sales rep. They've got 1200/2400 standalone and rackmount systems. And you don't call it the Bell 212 standard for nothing. Please note that I do not work in that department and know only the basics concerning such hardware i.e. it exists. I am not an employee nor an authorized representative of any part of AT&T, I only help solve problems for them on a contract basis. To think that my opinions are those of the company is ludicrous. Michael D. Gale "I just like blinking lights-the DECsystem 10 operator's panel is a work of art" blink-blink-blink-burnout-blink