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1200 buad modem designs wanted [message #82886] Mon, 10 June 2013 21:13 Go to next message
mikec is currently offline  mikec
Messages: 21
Registered: May 2013
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Junior Member
Message-ID: <701@reed.UUCP>
Date: Wed, 14-Nov-84 17:29:30 EST
Article-I.D.: reed.701
Posted: Wed Nov 14 17:29:30 1984
Date-Received: Fri, 16-Nov-84 06:42:09 EST
Organization: Tabr Sietch - Portland, Oregon
Lines: 26

[ This line is offered as a sacrifice so that others may live... ]

I am interested in building a 1200 buad modem either from a kit or
just from a design.  I know of many 300 buad designs and kits, but no
1200 buad versions.  This is probably because the 1200 buad modems
encompass an entirely different design.  Does anyone have a 1200 buad
design/kit they could send me?  Or even the address of some place to
contact.  Any info on costs and difficulties of building such a modem,
would also be apprecciated.

					Michael Cooper

______________________________________________________________________________
UUCP:
{decvax, ucbvax, pur-ee, uw-beaver, masscomp, cbosg,
 mit-ems, psu-cs, uoregon, orstcs, ihnp4, uf-cgrl}!tektronix--+
------------------------------------------	  teneron-----|
|          ||||||||||        LORD        |	  ogcvax------|
>         !||||      |      DIMWIT       <	  muddcs------|
|         ||||    ---|     FLATHEAD      |	  cadic-------+-!reed!mikec
|         |||C     CC \                  |	  oresoft-----|
>          ||||       _\                 < 	  grpwre------|
|           ||| (____|       OUR         |	  isonvax-----|
|            ||      |    EXCESSIVE      |	  nsc-pdc-----+
>             |______|      LEADER       <
---^----^----^----^----^----^----^----^---
Re: 1200 buad modem designs wanted [message #82918 is a reply to message #82886] Mon, 10 June 2013 21:13 Go to previous messageGo to next message
Andrew[1][2][3][4] is currently offline  Andrew[1][2][3][4]
Messages: 40
Registered: March 2013
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Member
Message-ID: <1170@orca.UUCP>
Date: Sat, 17-Nov-84 14:15:49 EST
Article-I.D.: orca.1170
Posted: Sat Nov 17 14:15:49 1984
Date-Received: Mon, 19-Nov-84 03:26:16 EST
References: <701@reed.UUCP>
Organization: Tektronix, Wilsonville OR
Lines: 18

[You see this line.  That's because it starts in column one.]

	"I am interested in building a 1200 buad modem either from a
	kit or just from a design ... Any info on costs and
	difficulties of building such a modem, would also be
	apprecciated."

A big difficulty is that you aren't allowed to hook the modem to the
telephone network until it's been certified by the FCC.  This isn't
something that an individual does on a hobby project; it takes the
resources of a company that's designing modems for a profit.

If you do hook up your modem without permission, and it brings down
some of the network, the phone company will Own Your Soul.  You're
liable for the entire cost of repair, including labor, and may find
yourself brought up on criminal charges.

  -=- Andrew Klossner (decvax!tektronix!orca!andrew)
Re: 1200 buad modem designs wanted [message #82922 is a reply to message #82886] Mon, 10 June 2013 21:13 Go to previous messageGo to next message
darrelj is currently offline  darrelj
Messages: 37
Registered: February 2013
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Message-ID: <1489@sdcrdcf.UUCP>
Date: Mon, 19-Nov-84 00:10:07 EST
Article-I.D.: sdcrdcf.1489
Posted: Mon Nov 19 00:10:07 1984
Date-Received: Tue, 20-Nov-84 03:16:59 EST
References: <701@reed.UUCP> <1170@orca.UUCP>
Reply-To: darrelj@sdcrdcf.UUCP (Darrel VanBuer)
Organization: System Development Corp. R+D, Santa Monica
Lines: 15
Xref: dcdwest net.micro:4096 net.wanted:3132
Summary: 

While the process for getting an approved phone line interface is indeed
arduous, you can by approved "black box" line interface which meet  the
requirements for you.  There are (1) full blown DAAs at $100 to $150
(2) small modules designed to be built in to modems (aimed at small
manufacturers or small lots to avoid certification hassles).
This is the easy part of building a 1200 bps full duplex modem.
-- 
Darrel J. Van Buer, PhD
System Development Corp.
2500 Colorado Ave
Santa Monica, CA 90406
(213)820-4111 x5449
...{allegra,burdvax,cbosgd,hplabs,ihnp4,orstcs,sdcsvax,ucla-cs,akgua}
                                                            !sdcrdcf!darrelj
VANBUER@USC-ECL.ARPA
Re: 1200 buad modem designs wanted [message #82930 is a reply to message #82886] Mon, 10 June 2013 21:13 Go to previous messageGo to next message
yamauchi is currently offline  yamauchi
Messages: 6
Registered: May 2013
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Message-ID: <4660@fortune.UUCP>
Date: Mon, 19-Nov-84 14:14:04 EST
Article-I.D.: fortune.4660
Posted: Mon Nov 19 14:14:04 1984
Date-Received: Wed, 21-Nov-84 00:16:44 EST
References: <701@reed.UUCP> <1170@orca.UUCP>
Reply-To: yamauchi@fortune.UUCP (Alan yamauchi)
Organization: Fortune Systems, Redwood City, CA
Lines: 31
Summary: 

In article <1170@orca.UUCP> andrew@orca.UUCP (Andrew Klossner) writes:
>
>	"I am interested in building a 1200 buad modem either from a
>	kit or just from a design ... Any info on costs and
>	difficulties of building such a modem, would also be
>	apprecciated."
>
>A big difficulty is that you aren't allowed to hook the modem to the
>telephone network until it's been certified by the FCC.  This isn't
>something that an individual does on a hobby project; it takes the
>resources of a company that's designing modems for a profit.
>       .
>       .
>       .
>  -=- Andrew Klossner (decvax!tektronix!orca!andrew)

Somebody correct me if I am wrong, but I believe you can build a 
direct connect modem without going thru FCC certification; however
you must use an FCC certified DAA to do so.  Off hand, I believe 
Cermetec and Novation build FCC certified DAA's, there are probably 
other manufacutrers also.  Anyway, the DAA's are EXPENSIVE in single 
unit purchases, they aren't even cheap in 100,000 unit pricing.  
It may be cheaper and less headache to buy a modem than build your
own.  Good Luck!

      Alan Yamauchi

UUCP:	{ihnp4,ucbvax!amd,hpda,sri-unix,harpo}!fortune!yamauchi
DDD:	(415)594-2436
USPS:	Fortune Systems Corp, 101 Twin Dolphin Drive, Redwood City, CA 94065
Re: Re: 1200 buad modem designs wanted [message #82969 is a reply to message #82918] Mon, 10 June 2013 21:14 Go to previous messageGo to next message
grunwald is currently offline  grunwald
Messages: 20
Registered: February 2013
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Message-ID: <4400078@uiucdcsb.UUCP>
Date: Wed, 21-Nov-84 15:24:00 EST
Article-I.D.: uiucdcsb.4400078
Posted: Wed Nov 21 15:24:00 1984
Date-Received: Sun, 25-Nov-84 03:31:20 EST
References: <4660@fortune.UUCP>
Lines: 3
Nf-ID: #R:fortune:-466000:uiucdcsb:4400078:000:141
Nf-From: uiucdcsb!grunwald    Nov 21 14:24:00 1984

If PLI's are around 100 to 150, how do these $9.95 phones manage to have a
be so cheap? They must have a PLI with spike cutouts, etc, right?
Re: Re: 1200 buad modem designs wanted [message #82989 is a reply to message #82918] Mon, 10 June 2013 21:14 Go to previous messageGo to next message
darrelj is currently offline  darrelj
Messages: 37
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Message-ID: <1494@sdcrdcf.UUCP>
Date: Mon, 26-Nov-84 10:06:00 EST
Article-I.D.: sdcrdcf.1494
Posted: Mon Nov 26 10:06:00 1984
Date-Received: Wed, 28-Nov-84 02:36:54 EST
References: <4660@fortune.UUCP> <4400078@uiucdcsb.UUCP>
Reply-To: darrelj@sdcrdcf.UUCP (Darrel VanBuer)
Organization: System Development Corp. R+D, Santa Monica
Lines: 30
Summary: 


The main reasons you can buy $10 phones but $100 interfaces (DAAs):
1)  DAAs have several relays rather than cheap molded switches
2)  The phone is self-contained.  As a result, max output can be done as a
byproduct of design (e.g. microphone saturates below limit).  Required
isolation from power lines done by 1/16 inch of plastic shell, etc.
An unrestricted DAA has to deal with some fool connecting 110V AC or a 100 W
audio output stage to line, and still achieve isolation (until it melts
down).
3)  Mass production.  DAAs are a specialty item, mostly holdovers from when
the phone company was paranoid or predatory about what you connect.  Modems
made in any quantity have it designed in as another $10 or $20 feature.
Darrel J. Van Buer, PhD
System Development Corp.
2500 Colorado Ave
Santa Monica, CA 90406
(213)820-4111 x5449
...{allegra,burdvax,cbosgd,hplabs,ihnp4,orstcs,sdcsvax,ucla-cs,akgua}
                                                            !sdcrdcf!darrelj
VANBUER@USC-ECL.ARPA

-- 
Darrel J. Van Buer, PhD
System Development Corp.
2500 Colorado Ave
Santa Monica, CA 90406
(213)820-4111 x5449
...{allegra,burdvax,cbosgd,hplabs,ihnp4,orstcs,sdcsvax,ucla-cs,akgua}
                                                            !sdcrdcf!darrelj
VANBUER@USC-ECL.ARPA
Re: 1200 buad modem designs wanted [message #85633 is a reply to message #82886] Mon, 17 June 2013 17:14 Go to previous messageGo to next message
adm is currently offline  adm
Messages: 22
Registered: May 2013
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Message-ID: <2297@cbneb.UUCP>
Date: Wed, 28-Nov-84 10:20:09 EST
Article-I.D.: cbneb.2297
Posted: Wed Nov 28 10:20:09 1984
Date-Received: Thu, 29-Nov-84 05:49:13 EST
Sender: adm@cbneb.UUCP
Organization: AT&T Bell Laboratories, Columbus, OHIO
Lines: 7
Nf-ID: #R:reed:-70100:cbnap:18000003:000:375
Nf-From: cbnap!whp    Nov 28 09:48:00 1984

AT&T now makes a two chip set, called the 882A switched capacitor modem.
These two chips perform all the functions of a 212A or a CCITT V.22; 300 and
1200 baud; synchronous or asynchronous.  Adding a third chip allows 2400 baud.
If you want to build a kit, it would be hard to find an easier one (just two
chips)!  (For any further info, contact your AT&T sales rep, not me)
Re: 1200 buad modem designs wanted [message #85656 is a reply to message #82886] Mon, 17 June 2013 17:14 Go to previous messageGo to next message
adm is currently offline  adm
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Message-ID: <2434@cbneb.UUCP>
Date: Fri, 30-Nov-84 20:39:29 EST
Article-I.D.: cbneb.2434
Posted: Fri Nov 30 20:39:29 1984
Date-Received: Sun, 2-Dec-84 02:50:07 EST
Sender: adm@cbneb.UUCP
Organization: AT&T Bell Laboratories, Columbus, OHIO
Lines: 7
Nf-ID: #R:reed:-70100:cbnap:18000003:000:375
Nf-From: cbnap!whp    Nov 28 09:48:00 1984

AT&T now makes a two chip set, called the 882A switched capacitor modem.
These two chips perform all the functions of a 212A or a CCITT V.22; 300 and
1200 baud; synchronous or asynchronous.  Adding a third chip allows 2400 baud.
If you want to build a kit, it would be hard to find an easier one (just two
chips)!  (For any further info, contact your AT&T sales rep, not me)
Re: 1200 buad modem designs wanted [message #85677 is a reply to message #82886] Mon, 17 June 2013 17:14 Go to previous messageGo to next message
adm is currently offline  adm
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Message-ID: <2571@cbneb.UUCP>
Date: Mon, 3-Dec-84 14:34:40 EST
Article-I.D.: cbneb.2571
Posted: Mon Dec  3 14:34:40 1984
Date-Received: Tue, 4-Dec-84 19:34:07 EST
Sender: adm@cbneb.UUCP
Organization: AT&T Bell Laboratories, Columbus, OHIO
Lines: 7
Nf-ID: #R:reed:-70100:cbnap:18000003:000:375
Nf-From: cbnap!whp    Nov 28 09:48:00 1984

AT&T now makes a two chip set, called the 882A switched capacitor modem.
These two chips perform all the functions of a 212A or a CCITT V.22; 300 and
1200 baud; synchronous or asynchronous.  Adding a third chip allows 2400 baud.
If you want to build a kit, it would be hard to find an easier one (just two
chips)!  (For any further info, contact your AT&T sales rep, not me)
Re: Re: 1200 buad modem designs wanted [message #111922 is a reply to message #82918] Mon, 16 September 2013 13:25 Go to previous message
notes is currently offline  notes
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Message-ID: <273@isucs1.UUCP>
Date: Sun, 27-Jan-85 02:01:27 EST
Article-I.D.: isucs1.273
Posted: Sun Jan 27 02:01:27 1985
Date-Received: Mon, 4-Feb-85 04:44:22 EST
Sender: notes@isucs1.UUCP
Organization: Iowa State University
Lines: 17
Nf-ID: #R:fortune:-466000:isucs1:9500002:000:768
Nf-From: isucs1!drew    Jan 22 18:02:00 1985

Exar also offers a 1200-baud modem chip set.  They also publish an application
note that gives a schematic diagram for a auto-sense 300/1200-baud modem.
You could connect it to the phone line through a simple acoustic coupler
(Ciarcia, in his Circuit Cellar article, "A Build-it-yourself Modem for Under 
$50", shows such a setup) or a direct-connect setup.

I once priced components for such a modem (with acoustic coupler).  You should
be able to build it (if you have sufficient technical knowledge and ability)
for about $200-$250.  You can write Exar at:

                       Exar Integrated Systems
                       750 Palomar Avenue
                       Sunnyvale CA 94088
                       (408) 732-7970

Hope this will be able to help you.
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