How Ma Bell Shelved the Future for 60 Years [telecom]

I take it that's for nothing more than preventing kinks when going around corners inside walls. I sort of assumed that it didn't address interference at all.

But that standard is for data, not voice. I figured it would work for voice.

That's what I figured.

Thanks.

Sure.

It's interesting that AT&T didn't switch over early for residential. After all, in the quanties they consumed, that would have driven down the per unit cost right off.

The two pairs are twisted _together_ instead of individually, so there is a lot of coupling and crosstalk between them. This used to be a big problem when people first started getting second lines for modems; the line noise would increase on one pair when the phone line on the second pair was in use.

Cat3 is just fine for the application; it's not as precisely made as Cat5, but it's a whole lot better than quad wire.

Sometimes you get lucky, sometimes you don't.

--scott

_I_ don't know the 'why' of it -- they didn't ask me for an opinion of the design -- but your supposition does sound reasonable. The helix is 'somewhat' better than absolutely straight wires, with regard to 'distant' noise sources that are approximately perpendicular to the cable run.

Is entirely 'adequate' for voice, if the reference is a human ear. Can adversely affect 'data over POTS' (e.g. Group III fax, "high-speed" analog modems, etc)

'wire' (in rational quantities) was not a 'billable' line-item, even on a T&M-based residential install. I don't recall if they even billed for the

-jack- itself, the "labor" rate of circa $70/hr ($17 per 15min increment, circa 1972) put the materials 'in the noise' as far as the customer was concerned. However, going from 'pennies' per foot (quad) to 'several tens of cents' per foot (Cat 3) plus requiring 'home run' wiring rather than daisy-chaining from the nearest jack _would_ have increased material cost

*tremendously*. To the point it likely _would_ have called for line-item billing. Whereupon the customers would have been screaming about the 'cost' that was ridiculously higher than what the neighborhood hardware store charged. That the higher-priced stuff is 'better" simply "doesn't matter" when the 'cheap stuff' _is_ "good enough" for the immediate need. A rationale of "you'll thank me in 20 years" (or even 10) doesn't cut it with most people.

That aside, the 'killer' fact is that *nobody* saw the revolution coming. Computers, even 'home' computers, were *expensive* (comparable to a good used car) and hard to use. Only an uber-geek would consider having more than one, *IF* said geek could _afford_ it. And a "network" was 'yet another'

*big* chunk of change (*hundreds* of dollars per 'node') on top of the cost of the base equipment.

Put 'expensive' wiring in -every- residence to support -that- kind of use? Even as of the early 1990s the reaction to _that_ would have been "you've

*got* to be kidding!!"

_Wiring_ for a network in the residence -only- became an issue when the

*cost* of 'a computer' had dropped to the point it was "reasonable" for _each_person_ in a household to have 'their own' unit, *and* 'networking' had dropped to the point that one "couldn't justify" the 'aggravation' of having to 'go to the computer room' to use a machine.

Having adequate ground clearance for a 'mountain' is *only* an issue when the mountain -does- come to Mohammed, and not the converse.

You could get bleed through from two simultaneous voice calls too.

I bought the small spool of quad wire at Radio Shack. I don't recall that they sold anything else for inside walls. They sold flat wire for the patch cord between the telephone set and jack, too.

I don't recall seeing Cat3 at consumer electronics stores or home improvement stores ever. Was this a mass market consumer item in the days before Cat5 became somewhat common? I do recall seeing Cat5 at Home Depot and Builders Square when big box home improvement stores were new but I don't recall that they offered a choice of Cat3 or Cat5.

I assume I'd have had to buy from Graybar if I wanted Cat3, and I might not have been able to buy a reasonably small quantity!

One useful purchase I made was Cat5 patchcord with factory-installed plugs for RJ-11 jacks that I could use for the modem. That eliminated some interference.

CAT3 is full of surprises. Something not well known is StarLAN which in today's parlance would be known as 1BaseT at 1Mbps and designed to work over existing telephony infrastructures.

StarLAN was also the first implementation of Ethernet over twisted-pair telephone wiring (). As the Wikipedia article states, StarLAN was patented by AT&T and also used by Hewlett-Packard and Ungerman-Bass.

And used by me as you can see in this 4-page extract from the O'Reilly "Managing uucp and usenet" book (now out of print):

which documents part of my (then) home office LAN circa early 1980s. At that time I had both StarLAN and normal Ethernet over coax. The funny thing is StarLAN actually was faster than "normal" Ethernet in real- world testing. I still have 3 AT&T 3B1 (aka UNIXpc aka PC7300) systems with both StarLAN and Ethernet cards installed; these systems also have an embedded (on the motherboard) 1200 baud modem. With StarLAN, I could and did connect my 3B1s to two Telebit T2500s on the LAN for UUCP and everyday dialup use.

The StarLAN network was a significant breakthrough in affordable inter- system communications with two major configurations:

1. per its name, a star, with a central hub serving many branches, and

1. with or without a hub, each branch serving up to 11 (IIRC) devices electrically daisy-chained and extendable 3x with additional hubs noting the hubs are named by AT&T as Network Extension Units.

"Devices" were manifold. Most common were interface cards for computer workstations. Very common were StarLAN:RS-232 Network Access Units (NAU) for adapting modems and other serial devices to StarLAN; I have many of these and they were also very useful connecting computers with only a serial console port or without other forms of networking.

The StarLAN hubs from AT&T were aka Network Extension Units (NEU) because they could join multiple other branches and/or hubs to cobble-up very large computer system and device arrays. What's really interesting is the concept of a Media Access Control (MAC) address pioneered with StarLAN as you can see in the rear-panel photo of one of my NAUs below.

Pictures of both a NEU and one of my NAUs taken a few minutes ago are here:

The white labels with black lettering are mine. The stamped labelling on the rear panel of the NAU may be difficult to read; from left to right the labels above each connector/button are: "DCE-RS232 A", "DCE-RS232 B", RESET, POWER, IN, OUT, PHONE. The IN and OUT are for daisy-chaining in a branch leg.

Here in Silicon Valley CAT3 was readily available at walk-in consumer-type stores such as Halted, Haltek, Jameco, Quement, U-Do Electronics, US Electronics, and even Fry's Electronics. There was another store in Sunnyvale near the intersection of El Camino and Sunnyvale-Saratoga whose name I've forgotten. San Mateo Electronics is another store I've been dealing with since the late 1960s -- they have stuff most people don't know exists (heh, try and find a caterpillar grommet in any store that's walk-in and doesn't require a business permit to enter).

Sadly, most such stores are long gone along with the demise of the great Heathkit company.

Pre-made cables were very common. 6', 16', 25' lengths.

Radio Shack carried 'bulk' Cat 3 "way back when". Just not in retail packaging, "on the shelf". There were a number (a small one, like maybe 6) of varieties of data cables that they sold 'by the foot', from a dispense/ measure mechanism in the back room. Much like the way the big box stores sell some types of electrical wire, for those who don't want/need a full spool.

It was there, but you had to know to _ask_ for it.