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Which acoustic coupler is compatible with an IBM 5150?

d4vid

New Member
Joined
Jan 25, 2021
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Location
Eugene, Oregon, USA
I want to use my cell phone with a novelty handset and acoustic coupler to dial into a BBS. Do I need a modem and acoustic coupler? What terminal software is generally used on a 5150? Thanks!
 
If you use an acoustic coupler, you won't need a modem too.

Mind you, the audio quality on many mobile networks is atrocious and iffy, so between random dropouts and things being psychoacoustically compressed to shit, you're not going to get something that's as good and as reliable as it used to be with the best and fastest of acoustic couplers on the best POTS lines. But at really low baud rates, I guess it might still work. Try it and report back.
 
thanks

thanks

Thanks for the info. While I was waiting for replies I went ahead and ordered a Hayes 2400 bps modem, and a Konexx Acoustic Coupler. The Konexx is battery powered and just has a phone line out that I'll plug into the LINE jack on the modem. I'll update this thread in a couple weeks when I test it out.
 
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To my understanding, a true acoustic coupler would not have required a separate modem; you would have used either–or. Another way to think of this is to say that acoustic couplers generally would have had the modulating-demodulating hardware built-in. You needed an acoustic coupler if (and way back when) you were not allowed to directly electrically connect anything to the POTS landline network. You instead placed the landline phone handset onto the acoustic coupler.

~~ Intermission: A few minutes later ~~

Some googling (including of the Konexx) revealed that my memory is incomplete: As this site puts it:
The acoustic coupler might also contain a modem, or the modem could be a separate device.
So apparently some simpler acoustic couplers did rely on a separate modem for the eponymous modulation/demodulation, and this also seems to be true for the Konexx. Since that's what you ordered, you probably did the right thing in also buying a modem too.

Things are not helped by the fact that some sources seemingly referred to acoustic couplers as modems, muddying the waters. Whether your acoustic coupler contained modulating/demodulating hardware or not, the main distinction would have been whether your kit was something you plugged into a phone socket in the wall, or whether it was some cradle-like thing you placed your or the company's telephone handset on.

NB: Softmodems/winmodems only became a thing later. I suppose they might work with a modem-less acoustic coupler. Maybe.

Rule of thumb: If your acoustic coupler has a serial port/cable that plugs into your PC, then it contains modem hardware. If it only has an RJ11 socket or phone lead, then it needs a separate modem. Apple's GeoPort might have been an exception, but I don't even.
 
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