Phone Point Connection

[plugwash]

Afaict old PABX's could work with either ordinary phones or analog phones with special features with most systems having a mixture.

Later the analog phones with special features were replaced by digital phones (using an ISDN like system I belive). I think most of them could still be configured to support analog kit though so people could connect thier fax machines etc. The phone system we have at uni certainly seems to have a mixture of ordinary analog stuff and digital stuff connectioned.

Some places have now moved over to VOIP systems. Even with voip systems though you can usually attatch analog equipment somehow if you need to.

 

[LoveRocket]

I challenge anyone to find a telephone manufactured within the last 20 years that won't ring without #3 connected.

You won't find one.

The master socket uses a very crude high-pass filter (ie a capacitor) to share the AC ringing signal onto #3 (wrt #2), BUT IT STAYS ON THE LINE PAIR TOO. All modern phones only connect to the line pair, so that's where they get their ringing signal from.

 

[Lectrician]

I can find you plenty - I could circle them in an argos catalouge.

It is very poor not to connect the ringer - it is a bodge. There are other ways to get ADSL working correctly.

PBX's come in many flavours. VOIP is becoming more popular for the trunk lines of PBXs, but not for extensions. High end PBXs can usually have a card added to provide some VOIP extensions designed for use for home/tele workers. (effectively an off site extension).

The majority of PBX's are HYBRID - they use a single pair for speech terminated to a master socket for connection to standard SLT phones. The same extensions can also support featurephones specific to the system (with screens, line and extension feature keys, hold buttons etc). The data for these is carried on a second pair and is presented on 1&6 on UK systems. Panasonic and couple others present it on 3+4 which means you have to change the socket to a secondary, which causes issues if someone swaps the featurephone for standard phone AS IT NO LONGER RINGS.

Larger systems have a selection of DIGITAL extensions using just a single pair presented to a secondary socket (or typically these days to an RJ11). They often have cards that can support standard phones, and these are more often used to support fax machines on DDI numbers etc, or phones where access to system features is not required regularly.

In short - MANY phones require a ringer. If you install extensions you should carry the ringer through. You should also have a phone in your van that is capable of testing to make sure you have connected the ringer. It is a bodge to leave it disconnected. You don't leave the earth disconnected in a socket "because loads of modern kit doesnt use an earth".

 

[AndyPRK]

I challenge anyone to find a telephone manufactured within the last 20 years that won't ring without #3 connected.

You won't find one.

That is *******s

 

[LoveRocket]

Fair enough guys, I'll bow to your superior wisdom on this this, I'm by no means a telephone expert. But I will say that in my experience I've never had a phone that wouldn't ring with only two wires connected.

Peace dudes.