Modems and external dialers.

[Electronics Plus]

-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Grant Taylor via cctalk
Sent: Wednesday, June 05, 2019 10:42 AM
To: cctalk at classiccmp.org
Subject: Re: Modems and external dialers.

On 6/4/19 8:30 PM, allison via cctalk wrote:
> Keep in mins the hardware for auto dial required some for of micro and 
> that was a post 1974 thing for the most part.

Why did it require a micro?  Could the host not perform the function 
that the micro would do?

> A few before that had a lot of TTL state machine to do that. 
> They obviously weren't cheap.

Why did that state machine need to be implemented in electronics?

Why couldn't that state machine be implemented in software on the host 
using the modem & auto-dialer?

> The dialer was often not at all as it was the human that dialed the phone.

~chuckle~

> I know of none that did both functions that required a second serial port.

Okay.

Reading the links that Ethan provided, it sounds like some auto-dialers 
did use a second port, but it was not a second (recommended) standard 
232 port.  Instead it was an RS-232 and RS-366.

Aside:  RS-366 sounds odd.  A combination of serial signaling and 
parallel signaling on the same port.  But not the same as a traditional 
parallel printer port.

> My first modem was a box about 12x8x2.5 inches and it was an all analog 
> modem good for 110/300 baud and it required connection to the phone line 
> (pre-modular connector) and you dialed the various (and relatively scarce) 
> BBSs and when you heard the tone hit the switch that put the modem on 
> the phone line and you would see the carrier and data lamps do their 
> thing. That was 1978ish.

Aside:  I assume that you're talking about before the small 6-position 2 
or 4 conductor plugs.  Or are you referring to the older than that 
not-quite-square 4 pin plug?  Or was the modem actually hard wired in 
with no plug / jack at all?

> A modem that could dial was maybe 1983-5 or so at affordable prices 
> (under 300$) for 300 baud.

*nod*

I have this mental picture, which I think is based on something I've 
seen at some point in the past, that was a device that attached / 
actuated / ??? a traditional rotary dial phone.  As in it had a finger 
that interfaced with the dial and something that could rotate it to dial 
the digit in question, rewind (term?), and dial the next digit in question.



-- 
Grant. . . .
unix || die

I used to have Rixon 212A autodialers. There were about the size of a Hayes modem, and only had 1 RS232 port and a phone jack on the back. I no longer have the modems, but I do still have one owner's manual in a binder. IIRC, the dialing was done through a software interface.

The other dialers mentioned before were probably twice the size of the Rixon.

I do still have one 300 baud acoustical modem in stock, if anyone is interested. AC adapter is included.

Cindy


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