[sdiy] question about cables

[Graham Atkins]

Cary,

In the mid 90's the broadcast company I worked for built a new "state of
the art" studio / production centre. In the central apparatus room,  
the audio
circuits from and to equipment and patchbays all went through Krone
termination frames and used solid core 10-multipair cables and IDC  
blocks
such as these :-

http://www.canford.co.uk/Products/20518/31-210-CANFORD-KHJ-CABLE-10-pair-BBC-PIN203
http://www.canford.co.uk/Products/40133/46-101-KRONE-ABS-Module

Graham

On 24 Aug 2009, at 17:47, Cary Roberts wrote:

>> The telephone systems are designed and built using matched solid
>> wire twisted pairs throughout the system.
>
> I've never heard the term "matched" or "twisted pair" when referring  
> to
> copper in a physical plant, inside or out.  POTS and T1 circuits are  
> at best
> on CAT3 which has three twists per foot.  There is a mix of 22, 24,  
> and
> 26AWG in every CO I've been in.  For voice, DSL, and T1 I've seen no  
> regard
> for matching length of tip and ring.
>
>> They do make extensive use of insulation displacement connections
>> in punch down blocks and other connector types.
>
> Very few offices use punchdown.  Most everything is wirewrap  
> including voice
> circuits.  Outside plant typically uses IDC for splicing and cross- 
> connects.
>
>> The entire system is designed for reliability and ease of rerouting
>> hardwiring, notably a lot of the IDC is reused when wiring changes
>> are made without a loss of reliability.
>
> Again, I've seen very little IDC in the central office.  Many CLECs  
> used IDC
> but wirewrap and soldered tree terminals still reign in most US  
> incumbent
> LEC offices for anything that is frequently moved, added, or changed.
>
> -Cary
> (who spent 4+ years running test and install crews for what is now the
> largest US telco provider)
>
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