Some More of My Diary

8/7/2019 Some More of My Diary

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Communication tools began to change

I started in computing circa Christmas 1983 the majority of computers that occupied desktops

where stand alone and never the twain would meet. However main frames passed data

backwards and forwards over expensive telephone lines through the night without anybody

knowing and had been doing so for many years.

Companies like AES Data had their own protocols which allowed them you set up links

between insurance companies based in America and link to Swindon in the UK which at thetime was a Mecca for this type of work. We (AES Data) had several companies that had links

between Swindon and LA. These links were not permanent they had to be initiated datapassed then link dropped.

As you would have read from an earlier blog IEEE moves took place to provide a method of

cabling, software and little gadgets called modems to allow desktop computers to be linked.

Here is a brief look at the equipment that went with the new protocols.

The Early Days

Modems originated as a way forteletype machines to communicate over ordinary telephonelines. In the late 1950s, AT&T developed the first commercial, mass-produced computer

modem, then called a "digital subset" (shown here, circa 1958), to linkSAGE computersacross the United States. It communicated at 110 bits per second.

The First Civilian Commercial Computer Modem

In 1962, AT&T introduced the Bell 103 Data Phone (seen here), which set the standard for

300-baud (approximately 300-bps) full-duplex modems. Until 1984, AT&T held a monopoly

on the phone system in the United States, so only AT&T could provide modems to work onits network. The monopoly stifled modem innovation until the 1968 Carterfone decisionopened the market for third-party phone devices, albeit in a limited fashion.

Acoustic Coupling

In the days of the AT&T phone monopoly, only AT&T had the right to connect electronic

devices directly to its telephone network. Companies got around this restriction by inventing

the acoustic coupler, which hooked a radio or modem to the telephone system via a cradle in

which the user placed a standard phone handset. This way, the modem would be acoustically

but not electronically linked, thereby avoiding any possibility of "damage" to the phone

system.

The First PC Modem

After the Carterfone decision, Non-bell Companies began selling computer modems. One of

the most notable for our purposes was the Hayes 80-103A, a 300-baud Bell 103A-compatible

modem that happened to be the first modem created for a personal computer. Dale

Heatherington (shown here) and Dennis C. Hayes designed it for S-100 bus computers of the

day, such as the Altair 8800 and the IMSAI 8080. Dale Heatherington


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The First Smart modem

In 1981, D.C. Hayes Associates introduced its seminal Hayes Stack Smart modem. The 300-

baud modem was the first to integrate its own command set--one that became an industry

standard. Using a series of ASCII strings sent to the modem through its RS-232 serial port,

users could initialize, autodial, answer, hang up, and more. Prior to this, most users had to

dial a phone number manually then hook up the modem once they heard an answer on theother end.

Early Home PC Modems

Modems for the early personal computers of the late 1970s and early 1980s were a mix of

direct-connect (where the user plugged the phone line directly into the modem) and acoustic

models. Some were "smart," copying the Hayes command set; others were dumb clones of

the Bell 103A standard and required manual dialling. Here we see (clockwise from upper

left) the Apple Modem 300, the Commodore Vicmodem, and the Atari 830. The highest

modem speed of the time was 1200 bps.

More Modem Madness

This interesting pile of PC modems from the 1980s and 1990s comes from Dave Dunfield's

personal collection. It showcases the wide range of shapes, sizes, colours, and materials used

in commercial consumer modems of the day.

The Early IBM (IBM) PC Era

From the mid-1980s onward, IBM PC clones dominated the PC market, leading to a new era

of internal ISA (and later PCI) modem cards designed for PC compatibles. External serialmodems held on strong, however, and around this time speedy 2400 bps modems emerged on

the market. Technology pushed that limit further over the years: first to 4800 bps, and then to9600, 14400, 28800, and beyond. Also during this era, modems gained the ability to send and

receive faxes.

Voice Modems and Soft Modems

In the mid-1990s (when modem speeds ranged from 28.8 kbps to 33.6 kbps), internal PCI

modems became such a commodity that prices plunged and vendors began to ship modems as

standard components of desktop PCs and laptops. This era saw the introduction of the"Winmodem," which offloaded some of the hardware processing to software on the

computer; this innovation also made them cheaper to produce. During the same period,"voice modems" that allowed voice calls to be handled through a PC arrived.

The Land of 56 kbps

In the late 1990s, modem manufacturers bumped up against the theoretical and legal limits of

analogue telephone data transfer speeds. These ceilings were about 48 kbps upstream and 56

kbps downstream with the aid of sophisticated technological trickery. Here we see a few

external 56-kbps modems, an internal PCI modem, and a modem in a PC Card format for

laptops.


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USB Modems

Though dial-up modems were once standard in PCs, they are becoming scarce due to the

predominance of broadband internet access. Companies still sell modems that connect

through external serial ports and internal PCI slots, but one common approach is to plug in a

tiny USB modem (like the ones shown here) when you need dial-up.

Beyond Dial-Up

Having reached the limits of analogue modem technology, companies tried various new

approaches to sate the public's demand for ever-faster modem speeds. The first alternative

was all-digital phone lines (ISDN), though their expensiveness limited their popularity. In the

early 2000s, modems that worked over cable TV lines won a following. Phone companies

also figured out how to deliver digital data more economically through ADSL lines. And then

there's wireless--another can of worms altogether.

Documents

Some More of My Diary