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ELR/TBR.



 
 
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  #1  
Old January 4th 06, 08:56 PM posted to uk.telecom
Dave
external usenet poster
 
Posts: 5
Default ELR/TBR.

On a phone in our office, it says ELR/TBR.

Does anyone know what this means since a Google search does not reveal
this and what this acronym actually does?

Thanks.
  #2  
Old January 4th 06, 09:07 PM posted to uk.telecom
Andy
external usenet poster
 
Posts: 67
Default ELR/TBR.

"Dave" wrote in message
...
On a phone in our office, it says ELR/TBR.

Does anyone know what this means since a Google search does not reveal
this and what this acronym actually does?


Earth Leg Recall or Time Break Recall.

It affects how the R or Recall button works on your phone telephone set. I
think UK home lines use TBR, but you may have a [telephone] switch at your
office that requires the other (not sure).

--
Andy.


  #3  
Old January 4th 06, 09:23 PM posted to uk.telecom
Ivor Jones
external usenet poster
 
Posts: 2,380
Default ELR/TBR.



"Andy" wrote in message

"Dave" wrote in message
...
On a phone in our office, it says ELR/TBR.

Does anyone know what this means since a Google search
does not reveal this and what this acronym actually
does?


Earth Leg Recall or Time Break Recall.

It affects how the R or Recall button works on your phone
telephone set. I think UK home lines use TBR, but you may
have a [telephone] switch at your office that requires
the other (not sure).


Most later PABX's and all normal exchange lines use TBR. Earth recall was
common prior to the mid/late 80's on PABX systems but is rare now.

For info and historical stuff on old phones and systems look he
www.thg.org.uk


Ivor


  #4  
Old January 5th 06, 06:57 AM posted to uk.telecom
Dave
external usenet poster
 
Posts: 5
Default ELR/TBR.

Andy wrote:
"Dave" wrote in message
...

On a phone in our office, it says ELR/TBR.

Does anyone know what this means since a Google search does not reveal
this and what this acronym actually does?



Earth Leg Recall or Time Break Recall.

It affects how the R or Recall button works on your phone telephone set. I
think UK home lines use TBR, but you may have a [telephone] switch at your
office that requires the other (not sure).

--
Andy.


Thanks, but what does "earth leg" and "time break" actually mean?
  #5  
Old January 5th 06, 09:00 AM posted to uk.telecom
Mike GW8IJT
external usenet poster
 
Posts: 150
Default ELR/TBR.

"Dave" wrote in message
...
Andy wrote:
"Dave" wrote in message
...

On a phone in our office, it says ELR/TBR.

Does anyone know what this means since a Google search does not

reveal
this and what this acronym actually does?



Earth Leg Recall or Time Break Recall.

It affects how the R or Recall button works on your phone telephone

set. I
think UK home lines use TBR, but you may have a [telephone] switch

at your
office that requires the other (not sure).

--
Andy.


Thanks, but what does "earth leg" and "time break" actually mean?


ELR means that pressing the Recall button earths one of the two incoming
wires.
TBR puts a very short open break on the normally closed (when phone is
in use) circuit. All new push button phones will do a Timed Break
Recall, which if pressed during phone usage will bring on the dialling
tone so that you can make a call with the original call on hold.
Pressing the Recall button again will restore the original call.
Hope this helps.
Regards Mike.

  #6  
Old January 5th 06, 11:42 AM posted to uk.telecom
Brian A
external usenet poster
 
Posts: 413
Default ELR/TBR.

On Thu, 5 Jan 2006 09:00:37 -0000, "Mike GW8IJT"
wrote:

"Dave" wrote in message
...
Andy wrote:
"Dave" wrote in message
...

On a phone in our office, it says ELR/TBR.

Does anyone know what this means since a Google search does not

reveal
this and what this acronym actually does?


Earth Leg Recall or Time Break Recall.

It affects how the R or Recall button works on your phone telephone

set. I
think UK home lines use TBR, but you may have a [telephone] switch

at your
office that requires the other (not sure).

--
Andy.


Thanks, but what does "earth leg" and "time break" actually mean?


ELR means that pressing the Recall button earths one of the two incoming
wires.
TBR puts a very short open break on the normally closed (when phone is
in use) circuit. All new push button phones will do a Timed Break
Recall, which if pressed during phone usage will bring on the dialling
tone so that you can make a call with the original call on hold.
Pressing the Recall button again will restore the original call.
Hope this helps.
Regards Mike.

As this is sometimes used for operating 'call waiting' the equivalent
to TBR is a short tap on the 'hook' or dialling a '1' on a 'loop
disconnect' phone.
Remove 'no_spam_' from email address.
  #7  
Old January 5th 06, 01:32 PM posted to uk.telecom
Jim
external usenet poster
 
Posts: 102
Default ELR/TBR.

Mike GW8IJT wrote:
"Dave" wrote in message
...

Andy wrote:

"Dave" wrote in message
...


On a phone in our office, it says ELR/TBR.

Does anyone know what this means since a Google search does not


reveal

this and what this acronym actually does?


Earth Leg Recall or Time Break Recall.

It affects how the R or Recall button works on your phone telephone


set. I

think UK home lines use TBR, but you may have a [telephone] switch


at your

office that requires the other (not sure).

--
Andy.



Thanks, but what does "earth leg" and "time break" actually mean?



ELR means that pressing the Recall button earths one of the two incoming
wires.
TBR puts a very short open break on the normally closed (when phone is
in use) circuit. All new push button phones will do a Timed Break
Recall, which if pressed during phone usage will bring on the dialling
tone so that you can make a call with the original call on hold.
Pressing the Recall button again will restore the original call.
Hope this helps.
Regards Mike.


Recall facility is required for access to in-call signalling
on a 2-wire line. Essentially it is used to switch between
speech and signalling, e.g. when a PBX user needs to
transfer a call to another extension. Single exchange lines
not connected to a PBX are set to time-break by default.

The ELR option needed a 3rd wire connection at the telephone
socket, presented on pin 3 of a BT outlet. PBX extension
wiring had an extra pair to the distribution point, which
was in turn linked to a system earth using an earth wire in
the multi-pair cable.

PBX earth recall was once regarded as more reliable than
time-break, which could be triggered accidentally via the
handset hook-switch. A bounce on hanging up could be
interpreted as a "hold" signal, and the call would not
clear. I'm not sure why it's become less common. Perhaps
it's because the third wire is harder to fit in with modern
extension wiring schemes, and also because modern business
phones are fully digital, with no need for an extra
signalling pair.

  #8  
Old January 8th 06, 12:04 AM posted to uk.telecom
Ian
external usenet poster
 
Posts: 229
Default ELR/TBR.

The ELR option needed a 3rd wire connection at the telephone
socket, presented on pin 3 of a BT outlet. PBX extension
wiring had an extra pair to the distribution point, which
was in turn linked to a system earth using an earth wire in
the multi-pair cable.

Well lets hope you didnt wire any large sites that way !


  #9  
Old January 8th 06, 02:09 PM posted to uk.telecom
Jim
external usenet poster
 
Posts: 102
Default ELR/TBR.

Ian wrote:
The ELR option needed a 3rd wire connection at the telephone
socket, presented on pin 3 of a BT outlet. PBX extension
wiring had an extra pair to the distribution point, which
was in turn linked to a system earth using an earth wire in
the multi-pair cable.


Well lets hope you didnt wire any large sites that way !



That's what the BS specified for earth distribution, so I
expect all large sites were wired that way. They couldn't
be certified otherwise.

It's not really a big deal. Most modern extension wiring is
3-pair. Older wiring was 4-core.
  #10  
Old January 8th 06, 04:28 PM posted to uk.telecom
Ian
external usenet poster
 
Posts: 229
Default ELR/TBR.


"Jim" wrote in message
...
Ian wrote:
The ELR option needed a 3rd wire connection at the telephone
socket, presented on pin 3 of a BT outlet. PBX extension
wiring had an extra pair to the distribution point, which
was in turn linked to a system earth using an earth wire in
the multi-pair cable.


Well lets hope you didnt wire any large sites that way !



That's what the BS specified for earth distribution, so I
expect all large sites were wired that way. They couldn't
be certified otherwise.

Since the introduction of LJU sockets the earth has always been on pin 4, (3
is the bell leg).
on a krone type DP the white/Orange would be connected to the earth bar. Not
sure about hardwired but as LJUs came in about the same time as the
electronic PBX I doubt many where hard wired, The Monachs I worked in the
very early 80s used the old style plugs.

Ian

It's not really a big deal. Most modern extension wiring is
3-pair. Older wiring was 4-core.



 




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