Modems and external dialers.

[allison]

On 06/04/2019 09:45 PM, Grant Taylor via cctalk wrote:
> Does anyone have any experience working with modems that didn't include
> internal / auto dialers?
>

Yes,
Novation cat, Hays, and a few others.  Dial the phone and put it in the
cradle or flip a switch.  Most of the 110/300boaud bel 101 and bell103
modems were "manual".

Keep in mins the hardware for auto dial required some for of micro and
that was a post 1974 thing for the most part.  A few before that had a
lot of TTL state machine to do that.  They obviously weren't cheap.

> They came up in a conversation in a newsgroup and I realized that I know
> of them, but know virtually nothing about them.
> 
> I think they were separate devices, which probably means that they
> likely had separate serial ports to talk to each of them.  Did they
> support some sort of pass through?  Or did they really require two
> serial ports on the host?

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

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

For example the DEC ealy modems required the user to dial the phone and
pushing a button would connect it.  THe DEC modem had a protocal was
different from the later ATDT (Hays modems).

My first dial up was 1969, Bell 103 external to the TTY.  Later versions
had rotary dial or touch tone and the modem in the TTY stand.

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.

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

Allison