Network Evolution

Ever since my first personal computer I’ve had some kind of network connection.  For the SOL it was a 300 bps (bits-per-second) acoustic coupler.  In those days the telephone company didn’t allow any kind of direct electrical connection to the telephone network except for equipment they supplied.  In fact, my first telephone answering machine was also acoustically coupled.

 

I could connect my computer to other hobbyist’s personal computers that ran BBS (Bulletin-Board System) software.  Typically such systems had only one phone line, so if someone else was connected to the system, then I would get a busy signal. 

 

I could also connect to commercial time-sharing systems.  The first of these was called the Source.  Later came CompuServe, which I subscribed to.  It had a strictly character-mode interface.

 

When the Macintosh came out, America Online began a client-server based system:  You downloaded the AOL client program which talked via a proprietary protocol to the AOL server machines.  I never used AOL; my modem was not on my Macintosh.

 

When I worked for Bank of America, they supplied me with a phone-company 212A modem and my data rate jumped to 1200 bits per second. 

 

When I moved to Japan, I was not on the network.  We did have some modems at work that I used to connect to the corporate computers in California. Sometimes that worked, and sometimes it didn’t.  I think it depended on whether I got a satellite or undersea-cable circuit.  The Japanese telephone company, NTT (Nippon Telephone and Telegraph), was much more restrictive than AT&T about connecting modems to their network.  Even with an acoustic coupler we had to file a network plan with the phone company, and they came to inspect our modems once they were installed.

 

When I returned from Japan, Calma had a connection to the Internet.  We could only use it from work, not from home.  There was no World Wide Web yet, but we could exchange email, and files, and “telnet” from one computer to another.

 

From home, I could dial into a UNIX system at work and start a “shell” or command prompt.  Thus I could, from home, remotely enter commands to the UNIX system at work.  I could therefore connect from that system to the Internet.  My home computer was not directly on the Internet, however.

 

At some point the phone company started allowing third-party direct-connect modems.  This probably had to do with the breakup of AT&T, and the end of the Bell-system monopoly.  As the technology improved, data rates climbed to 2400 bps and eventually 56 kbps.

 

Also around this time simple point-to-point connections were begin replaced with software that ran SLIP (Serial Link Internet Protocol) or later PPP (Point to Point Protocol).  These allowed our home computers to become full-fledged nodes on the Internet. 

 

While at Tandem I was given an ISDN (Integrated Service Digital Network) phone line.  This carried both voice and data as digital circuits. I don’t remember the speed, but it was certainly faster than a modem.

 

By the time I left Tandem, ISDN technology was being replaced by DSL (Digital Subscriber Line).  This was a digital circuit that was modulated onto a high-frequency carrier on the customer’s analog telephone line.  It’s what I’m using now.  I’m guaranteed a download rate of 384 kbs and an upload rate of half that.  But I often get rates substantially faster than that, up to over 1 mbps.