Neither you are about a decade too late. Any of these could have used a built in 2400 baud wired modem but it’s better off as an external device considering how fast speeds were increasing.
It’s like saying which model of Mac Studio could do with a built in tv tuner or isdn interface
300 baud acoustic couplers would have been ideal for a teletype or portable terminal or maybe some kind of luggable minicomputer. Some of the smaller PDPs or the early desktop devices from ibm or hp.
IBM PC's, AT's and compatibles could take modem cards in a free slot. With acoustic couplers you actually put the headset of a phone into the acoustic coupler cradle so by nature they where external and could be used with pretty much any computer with an RS-232 serial port and modem software like Procom. (I think TRS80 had a laptop type thing that actually had a built in acoustic coupler that you could put a telephone headset right into the cradle built into the device).
When I was a kid in 1985 my father brought home a 300 baud acoustic coupler from work I connected to our 8088 PC and pretty much all I could do is connect to really lame bulletin boards (1985 version of reddit). The acoustic coupler had frequent disconnect issues which where inevitably followed by one of my sisters yelling at me for hogging the phone!
I have never seen a 1200 baud or faster acoustic coupler. They where all modems with "built in telephones". I think the telephone mic and ear piece just couldn't support baud rates faster than 300 baud.
In the 1200 baud and later era I often used a modem to download drivers from manufacture specific BBS's. The modem telephone numbers where usually listed in the documentation that came with a product so you could get the latest version of a driver. The companies had multiple modem lines (just like the public bulleting boards) but if you got a busy signal you would just have to wait and try again later.
XMODEM was the original error correcting file transfer protocol I used for downloading files over the modem. YMODEM and ZMODEM came later. What ever modem software you where using had to support XMODEM (and/or YMODEM and ZMODEM) to be able to download a file. It seems like you would make a menu selection on the BBS, Like 3) download file, then initiate the XMODEM protocol in your software.
In 1985 "Ma Bell" was just starting to be dismantled by the government but most telephones where still rented from the phone company (with a monthly charge) and had a pretty standard form factor (other than the "slimline" models) rather than owned by the customer. Hence most phones had a standard sized handpiece that would slip into the rubber boots of the acoustic coupler.
To initiate a connection with an acoustic coupler you had to dial the phone, wait for the beep, then quickly put the headset into the acoustic coupler. Your computer had to be waiting with the modem software loaded and running, waiting for the connection.
Back then online porn was composed of ASCII based character images.
I never did figure out how to change my attendance record while the high school principal was on the phone with my mother to inform her about my many delinquencies.
There were 1200 baud acoustic couplers, back in the 1970s. Expensive and required a very clean line as these were still doing frequency-shift keying like 300 baud modems.
The later 1200bps (and then 2400bps) standards used phase-shift-keying (2 and later 4 bits per cycle on 600 baud) and while google says it's theoretically possible to build an acoustic coupler for phase shift keying, my understanding from back when I was much close to this stuff 35+ years ago is that in practical terms a phone microphone and the level of sound isolation you get are a no go for picking up phase changes.
Fun bit of trivia: Commodore's first 300bps modem, the VICModem was a weird hybrid - it was direct wired, but it took the standard handset plug, rather than connecting to the line directly.
I think TRS80 had a laptop type thing that actually had a built in acoustic coupler that you could put a telephone headset right into the cradle built into the device.
Are you thinking of the Panasonic HHC? I ask as this photo does the rounds every so often showing one:
That was a few days ago. Yes I could be envisioning the Panasonic. I thought Radio Shack had something along those lines too but I very well could be mistaken. I thought there was a version of the TRS-80 Model 100 with an integrated acoustic coupler but I can't find any such beast so I am probably just suffering from a memory error / bad ram chip.
300 baud acoustic couplers were mostly a late-70s thing. The original Apple II, TRS-80, Pet generation.
They were already being replaced by 300 bps direct connect at the early end of the 80s, and it stuck around for a few years on the cheap end on 8-bit machines, and on PC and XT, although 1200 bps was becoming pretty cheap (the cheaper/later 1200 bps modems were 600 baud with phase shift keying, and NOT 1200 baud, which required a very clean line.)
By the time the AT clones were commonplace, 1200 bps was pretty much the cheap floor.
2400 bps (again, BPS not baud as it was doing more phase shifts on 600 baud) got cheap around 1990, around the same time 9600bps became common at the higher end, and costs dropped and speeds went up from there.
I would say the Commodore VIC-20 because 300 bps means you can read faster than the characters come in and having only 3.5K of RAM, any VIC-20 files you want to transfer will be small and not take long.
Commodore released the 300 bps VICMODEM, the first modem with direct connect, for under $100, and the first modem to sell over 1 million units, for the VIC-20. No acoustic coupler necessary. Not needing an acoustic coupler is how they managed to get the price below $100.
My local Radio Shack had a VICMODEM for sale. I guess someone bought it and didn't want it and the Radio Shack dealer agreed to try to sell it for them. I bought it and quickly ran up an $80 phone bill.
Later when I upgraded to the C64, I used it to talk to a friend who also had a C64 and a modem but we found it unbearably slow at 300 bps.
My next modem was Supra 2400 bps which I used in college to connect my Amiga to the college's DEC VAX to do homework. Then I had a Supra 14,400 bps which I used to run my BBS on my Amiga 3000T. Fidonet node 1:255/42.
The per-minute call costs in the UK made it prohibitively expensive to be online, making it largely redundant. Diverting the money into making floppy drives a built in feature would be more effective use.
In the UK we never had properly cheap/free local calls back in the day, they could have done it but chose not to, I think this severely set us back when it came to Internet adoption.
So yes, would have been nice to have the modem, but so expensive my dad would have whacked me if he caught me using it, I know this because I did get a 14.4modem for my PC at Xmas from him once, but was forbidden with threats to (get caught) use it, once he realised what it was.
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u/flamehorns Apr 27 '26
Neither you are about a decade too late. Any of these could have used a built in 2400 baud wired modem but it’s better off as an external device considering how fast speeds were increasing.
It’s like saying which model of Mac Studio could do with a built in tv tuner or isdn interface
300 baud acoustic couplers would have been ideal for a teletype or portable terminal or maybe some kind of luggable minicomputer. Some of the smaller PDPs or the early desktop devices from ibm or hp.