History of wiring configs.

[djtt]

Does anyone have any links to the history of telco, wiring confifg..

For example how they developed the color coding, the pair counts, 66 block pin configs and such. The reason for the numbers fo pairs in cable trunks and so forth.

Thanks !

 

[mikeydidit]

Still looking but here is one you guys will enjoy. I think some of the guys here may be in some of these pictures... .

http://www.porticus.org/bell/oldphotos_9.html

Also look around the site for more.

"A people that values its privileges above its principles soon loses both."
- Dwight D. Eisenhower (1890-1969), Inaugural Address, January 20, 1953

For the best response to a question, read faq690-6594

 

[mikeydidit]

This one is pretty cool also.

http://www.datacottage.com/nch/cablinghist.htm

"A people that values its privileges above its principles soon loses both."
- Dwight D. Eisenhower (1890-1969), Inaugural Address, January 20, 1953

For the best response to a question, read faq690-6594

 

[djtt]

Do you guys know how the color coding of cable paris came into play?

I often wondered why they choose the colors and formats they did.

Thanks!

 

[SYQUEST]

The Bell System developed the EVEN COUNT color code in the early 1960s. It seems to be based on a 25 pair count, broken into 5 pair groups with repeating colors or tracers. Each lead has two colors, one is common for that group or tracer. The multiple 25 pair units within the same jacket or sheath, were called binders with the same repeating color code.

BLUE ORANGE GREEN BROWN SLATE

WHITE RED BLACK YELLOW VIOLET

There were some variations of this design for 20 pair cables or units where there was no VIOLET group. A lot of CO equipment used 20 pair cables/groups, and the CALL DIRECTOR™ telephone sets used line cords with 20 pair binders (120 conductors and 200 conductors).

This color code design and plastic (PVC) insulation sure made it easy for cable splicers compared to the old pulp insulated copper conductors and the "toning" methods used for pair identification.

During that time period, Bell Labs was very busy with all kinds of improvements and introduction of new hardware and equipment. In 1961 the Bell System introduced the 66 type connecting block series to replace the old binding post type and to eliminate soldering and the amount of labor required to install even a key system. But even before that, with the introduction of the Call Director™ in 1958, brought a significant improvement in station equipment by utilizing Amphenol's "ribbon" connector for multiconductor line cords.

This one item may have the influenced the 25 pair count concept for the EVEN COUNT COLOR CODE, since they had 50 contacts. The old color code was a mess:

RED GREEN YELLOW BLACK SLATE-YELLOW SLATE-BLACK BLUE WHITE BROWN-GREEN SLATE-BLUE SLATE-WHITE and so on, etc.

Hope this helps!

....JIM....

 

[djtt]

yes, very informative and has answered some questions about this equipment. I actually collect old unusual and short lived business equipment from the late 50's to early 70's. i.e. the Call Director and Dimension PBX series.