On Sat, Dec 1, 2018 at 3:10 AM Chris Fezzler wrote:
>
> My friend and I want to show some of our kids how journalists filed stories
> with the old MT.
> We have two MT100 and two sets of "cups."
>
> Can we somehow rig two old phone receivers to make it simulate a landline
> call over the modem cups (in the same room, on the same table?u
well, yes, there're various options to simulate a landline if you want
to use real telephones. None of the options is really too easy, but
not impossible indeed.
However, if you need this setup only once for a little show, you might
not want to invest your time and some money on it.
First option would be to modify the two phones (or at least one of
them) to use a local battery (normal PSTN phones are internally wired
for central battery operation), so once you have
local battery phones, your landline just becomes two wires between the
phones. You can't ring one phone from the other in this case (unless
you also add an AC voltage generator for ringing the other phone) but
you can communicate between them as if they were connected to a normal
landline.
I can't really point you to a recipe to modify a normal
central-battery phone to local-battery operation, I have several of
the two species and I've just drawn the simple internal schematics
whenever I wanted to convert one kind to the other kind. I'm speaking
about all analog phones, no electronics, just transformer, wirings,
carbon microphone and speaker.
The local battery on each phone can be almost anything from 4V up to
12V, I used to use "flat" 4.5V batteries that were widespread in Italy
until the late '90s, or 9V batteries.
Second option: get an old analog office exchange, the smaller, the
better. There're old office exchange device with 8 analog ports.
You might need to repair a bit what you find and learn how to use it
(might be just enough to connect the two phones to two ports and dial
the internal number of the other port).
Third option (what I have to test old analog modems): get an asterisk
(or FreePBX) small server, a raspberry PI3 is usually powerful enough,
I had a small thin client PC doing nothing, so I used that. Then get a
two port ATA (I have a CISCO SPA-2102, two port analog phone to SIP
adapter, there're many other models around, cheap), configure the
asterisk server with
two extension, one for the first ATA's port and one for the second
port and you can dial between the two ports. The asterisk exchange
server and the ATA are connected via an ethernet cable.
I think FreePBX is easier to configure, but I've made the setup in one
weekend easily from scratch, just reading some informations on
internet.
The only problem of the SPA-2102 is that it doesn't recognize pulse
dialing (yes, I'm using very old phones with the rotary dial), but
that is a minor issue for me so far (I can use a DTMF generator on the
smartphone for example). There's one ATA, the Grandstream HT-502, that
is reported to work with pulse dialing, but I preferred to use an ATA
that's more widespread, should I have some configuration issue (but I
didn't have any issue in the end).
There may be other options, but I mentioned only what I tried myself.
HTH
Frank IZ8DWF
>
