a question on the old days of comms

Beano

I was having a nostalgic conversation earlier about the good ol' days of 56K modems and the joys thereof. I had a look at the wikipedia article on them and something is confusing me. In the section on speed it says :

In 8-N-1 connections (1 start bit, 8 data bits, No parity bit, 1 stop bit), which were typical before LAPM became widespread, the actual throughput is a maximum of 5.6 kilobits per second, since ten bits are transmitted for every 8-bit byte

56K modems ran at 56kilobits a second nominal speed. that is 7 kilobytes a second. take off the start and stop bits that leaves 5.6 kilobytes a second actual throughput. where is the article getting 5.6 kilobits a second from?

niallb

It's a mistake. 56k modems would transfer close to 5 kilobytes per second.

56k modems varied wildly though, and depending on your ISP, you might as well have had a 33k one, because that was as fast as the shared standards would go.
Generally a good link would give you transfers of about 3.5kb per second.
If you did your homework and bought a modem that supported the same standards as your ISP's on the other end you might stretch it a bit.

Beano

thanks for confirming that i havent gone totally senile. I would edit the article and correct the mistake but i'm sure some cretin would come along 5 minutes later and revert the change. Now excuse me while i go and tell some kids to get off my lawn.

rozeboosje

ZOMG how did people ever get pr0n in them days?

Alun

56k modem? Luxury!! ... my first foray into the online world (Bix (Byte Information eXchange) and CompuServe) was done using a 300bps acoustic coupler

http://en.wikipedia.org/wiki/Acoustic_coupler

Beano

you must be even older than me. I think i remember using an acoustic coupler to connect to a bulletin board but i dont think it was as slow as 300 baud.

Alun

Yes, I'm pretty ancient Acoustic modems were only 150 or 300bps IIRC. After that it was good old Hayes or Hayes compatible modems from 1200bps upwards.

rozeboosje

BUT YOU COULD ALMOST TRIGGER WWIII WITH THOSE I KNOW IT'S TRUE I SAW IT IN A MOVIE ONCE O_o

Beano

that wasnt a movie it was a documentary.

FSL

The first data transmission I used involved an audio coupler and the data was transferred from a reel of magnetic tape on one end to another on the other. The state of the art mainframe, an IBM 360/50, had 512k bytes of memory. The data transmission was a completely separate unit.

niallb

Anyone else remember building a light sensor and taping it to the television during a BBC show to download software encoded into light pulses...

MrTime

niallb wrote: »

Anyone else remember building a light sensor and taping it to the television during a BBC show to download software encoded into light pulses...

Think it was Tomorrows world on BBC
a BASIC program
recorded to audio cassette

probably for BBC micro ; or maybe even Sinclair ZX80

niallb

MrTime wrote: »

Think it was Tomorrows world on BBC
a BASIC program
recorded to audio cassette

probably for BBC micro ; or maybe even Sinclair ZX80

Close - ZX-81!