Component Descriptions

[Old Sparky]

Is it necessary to refer to a jack socket as such.  I once read somewhere or other, that, to a plug 'a jack is a socket!

[Brianc]

I believe in old GPO terminology, the male bit of the old telephone/audio connection system is called a plug, not a jack plug and the female bit is called a jack, not a jack socket. The socket is called a jack as it is normally used as a way of jacking into a circuit. However, the names seem to have morphed into jack plug and jack socket used nowadays. A row of jacks is still called a jackfield and not a jacksocketfield!

[Terry]

I'm in agreement with Brian here.

I think the confusion comes about because GPO terminology seems, largely, to have been confined in-house in the past, so that, in the outside world, people have used their own previous experience of plugs and sockets and applied it to the GPO terminology.

However, I don't think that all of these descriptions are that clear cut. Some years ago, an Indian colleague whose second language was English and whose technical knowledge was confined to his CATV experiences, joined a commissioning group responsible for the roll out of both CATV and Telephony.

Serge was confused by a discussion in which 'the Switch' was referred to several times so I leaned over and told him that 'the Switch' was what he would know as a Telephone Exchange.  Our manager promptly rebuked me for using such an expression (!), saying that the Exchange is the building that houses the switch!

Unfortunately I wasn't quick enough of the mark to ask him what the 'X' in PBX and PABX stands for ...

When our VM phone died a couple of weeks ago, the engineer seemed to be getting some confusing readings outside and said he was going to the street cabinet so I told him that our line was on pair one and that it was also pair one at the cabinet up the road, which surprised him slightly until I told him that we'd had a problem before when an engineer had left his test phone jacked into our line!

After a bit more to-ing and fro-ing without a result he announced  that he was going back to 'the Exchange'. Now apart from missing out a very important part of the network, the Switch is a mile and a half away and he certainly didn't have time to get there and back before he returned. Service was restored and he said there'd been a probem 'back at the Exchange'

So I asked him if he meant the Switch or the TDN* ...

* Cable telephony, like the CATV & Internet, is distributed to the local area over fibre, terminating respectfully at the CDN (CATV Distribution Node) or the TDN (Telephony Distribution Node).

The CATV signals are modulated onto the light as analogue signals and are easily recovered - the fibre receiver is usually integrated into the Launch Amplifier - but the telephony traffic is digital and requires a lot of intelligence in the street cabinet before final D/A conversion.

[boater sam]

Ah, yes, ones a jack.
Wonder; if the other was known as a Jill it would be self explanatory?

[Brianc]

Ah, yes, ones a jack.
Wonder; if the other was known as a Jill it would be self explanatory?

The problem is that it's the wrong way round!

[Alan Douglas]

I've never heard "jack plug" or "jack socket" here. They're just plugs and jacks, although some people do confuse the terms. "Jack field" I'm sure I've seen but that would be old technology now.

[Brianc]

"Jack field" I'm sure I've seen but that would be old technology now.

Not in the Broadcast industry, Alan, although they are dying out now. They were used both in vision and sound circuits to enable fault finding and re-routing signals required by equipment failure.
The largest assembly of jackfields I was ever involved in was the first installation in the ITN building in Gray's Inn Road, London. We installed 2 off 132 x 132 component analog vision matrices with all i/ps and o/ps through MUSA type jackfields (the MUSA is a connector designed especially for patching high frequency circuits in an aerial array that could be steered by altering the phasing of certain elements of the array using a MUSA patch panel - a very British connector!). As it was an analog component system, each 132 x 132 matrix had three levels giving a total of 1,584 circuits, each wired via a vision jackfied. The jackfield occupied more than 3 racks of real estate (132U).