Hot answers tagged

121 votes
Accepted

Why did modems have speakers?

Much of this has been covered by previous answers, but to try to summarize: Adding a speaker was cheap and easy. The additional parts were standard, reliable, and inexpensive. It provided rich, ...
  • 2,696
108 votes
Accepted

What technological factors drove the rise of "high-speed" modems in the early 1990s?

Up to 9,600 baud it's just iterative application of fairly straightforward analogue-domain ideas as and when standards emerge. Then there's a significant improvement on the digital side that bumps to ...
  • 32.8k
63 votes

Why did modems have speakers?

Not all modems from back in the day had speakers, for example an early popular modem was the Hayes Micromodem II (available for Apple ][ and S-100 machines) and it did not have a speaker. But the ...
  • 14.7k
33 votes
Accepted

What was the technical reason behind the octal digits used for CompuServe User IDs?

It appears to be a legacy from TOPS-10. The easy part: octal was more popular in the 60s and 70s in general, but especially at DEC, which produced a number of 18-bit machines; the 3 bits per symbol ...
  • 4,012
32 votes

Why did modems have speakers?

So why were modem speakers such a persistent feature, and "fixture" of the time? Three basic reasons: Adding a simple amplifier and a speaker is the most easy way to handle unexpected situations In ...
  • 184k
30 votes

How can I construct a dial-up network in my home, purely for the kicks?

A/the correct solution would be to set up some sort of small local PBX. In the spirit of retro you can probably score an analogue PBX for not very much money and the mechanical ones are arguably even ...
  • 9,850
27 votes
Accepted

What exactly were those large orange chips on the Hayes Micromodem II interface card?

The 207C300 and 207C400 are "active filters for use with modems." They were manufactured by Sprague. I found an advertisement for them in Electronic Design magazine, volume 26, number 4, ...
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22 votes
Accepted

How did XBAND modems transmit game state?

Many games played over the Internet today use a client-server model, where the server has a full copy of the game state, and distributes appropriate pieces to the connected clients. Due to the ...
  • 7,771
22 votes

Why were "data modems" so much more expensive compared to "fax modems" back in the day?

Fax machines use distinct frequency ranges for upstream and downstream transmission, with one direction receiving the vast majority of the bandwidth. Computer modems at 9600 and higher baud rates ...
  • 31k
21 votes

Why were "data modems" so much more expensive compared to "fax modems" back in the day?

I'll add a detail to the topmost answer. Data modems up to 2400bps used different frequency bands for transmit and receive. But why? Look at your telephone wire. There are only two wires going ...
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20 votes

Why did the Bell 103 modem use a data rate of 300 bps?

300 bits per second has the advantage that it is the lowest common multiple of both 50 and 60. These made it easier to use the power line frequency (50 Hz in Europe, 60 Hz in USA) to synchronise the ...
  • 201
19 votes
Accepted

What was the service offered by US Sprint for long distance data connections in the late 1980's?

It sounds like what you're looking for is Telenet (renamed to "Sprintnet" when Sprint acquired it) or Tymnet. Tymnet did not survive and Sprintnet became part of what we now know as the Internet.
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19 votes

Why Kansas City Standard (KCS/CUTS) differs from Bell 103/202/212 modem protocol?

They are different because they are meant for different use cases so they both work well for what they are meant for. One is suitable for real time data transmission between two distant equipment over ...
  • 21.3k
19 votes

Why was Wireplay "faster and more reliable" than dial-up Internet would have been with the same hardware/infrastructure?

This article from British Telecom says Wireplay launched in June 1996 as a way to host multiplayer games over a closed dial-up network. This is why it was "non-Internet": All players were ...
  • 3,453
18 votes

Whatever happened to the janus protocol

Short answer: Because it was useless to begin with. For a more detailed answer the whole picture is needed: Back in the real old days modems were symmetrical. A V.21 modem split the line into two ...
  • 184k
18 votes
Accepted

Why did the Bell 103 modem use a data rate of 300 bps?

10 CPS/110 Baud was the maximum rate these signals could be sent with acceptable sidebands using an all-mechanical system. 300 was 3 times the teletype speed, and that limit is set by the 4 kHz ...
  • 781
15 votes

Why did the Bell 103 modem use a data rate of 300 bps?

A very good first answer however I would also like to note that any data rates above 300bps could not be acoustically coupled and were direct connect modems only. And anything 33.6K and above ...
13 votes

What exactly were those large orange chips on the Hayes Micromodem II interface card?

So my question is, what is the deal with these chips and why do they seem unique to this particular interface card? While the orange colouring is quite flamboyant, the use of hybrid circuits/modules ...
  • 184k
11 votes

Why did modems have speakers?

I suspect it could be a holdover from the days when a modem was a box that connected between your terminal and your phone. The phone handset was used to dial the remote number; when you heard the ...
  • 29.2k
11 votes

Why was Wireplay "faster and more reliable" than dial-up Internet would have been with the same hardware/infrastructure?

If they still use the same modem, and the same telephone wires, why is "not using the Internet" faster and more reliable for playing (supported) games "online"? The internet is a ...
  • 4,012
10 votes

What technological factors drove the rise of "high-speed" modems in the early 1990s?

The early 300 bps modems used frequency shift keying (FSK), whereby sound is generated at one frequency to represent a '0' and a different frequency to represent a '1'. Standards prescribed what ...
  • 101
10 votes

What was the technical reason behind the octal digits used for CompuServe User IDs?

CompuServe was initially a Time-sharing system utilizing original DEC PDP-10 machines. You would log in as a regular system user and run your programs. The credentials of these systems consisted of ...
10 votes

Why did modems have speakers?

All the answers above have concentrated on outgoing calls but modems also took incoming calls and, because phone lines were expensive, it was unusual to have multiple lines for fax, data, and voice. ...
9 votes

Creating Null Modem Connection between two C64s?

"Null modem cable" may not quite be a misnomer but is potentially misleading: it is a cable that connects two computers via their serial ports without modems. It's not a null cable for modems, it's ...
  • 32.8k
9 votes

How was parity used with modems?

By the time I got my first analog modem, around 1980, my experience was the same as yours. Even and odd parity on 7-bit data was available, but almost all the BBSs featured 8N1. (The modems even still ...
  • 8,223
9 votes
Accepted

Cartridge modems - was the Vic-20 a special case?

I thought the RS-232 port on the Vic-20 was completely separate from the cartridge port, so a thing had to be plugged into one or the other, and if the modem was plugged into the latter then it could ...
  • 184k
9 votes

Why did the Bell 103 modem specification use 1070Hz, 1270Hz, 2025Hz and 2225Hz?

Why were these specific frequencies chosen other than needing to fit into the voice band Erm, in the end it's all about fitting in the voice band of 300..3400 Hz. For one, 1 kHz and 2 kHz are almost ...
  • 184k
9 votes

Is there a softmodem driver package for Linux?

There is the Linmodem project, made by (who else) Fabrice Bellard. Unfortunately, it is more of a proof-of-concept than a working, ready-to-use driver, and it has been abandoned in that state in 2000....
  • 18.8k
9 votes

Why Kansas City Standard (KCS/CUTS) differs from Bell 103/202/212 modem protocol?

TL;DR: Three reasons: A cassette interface only needs to fit a single transmission channel at a time, while a modem needs to hold two. Cassette tape is made for a different (broader) frequency range ...
  • 184k

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