DACS - Revision history

Kitz: Category

2024-05-18T08:35:46Z

Kitz at 19:33, 24 January 2012

2012-01-24T19:33:42Z

Kitz at 18:58, 24 January 2012

2012-01-24T18:58:50Z

Kitz at 18:45, 24 January 2012

2012-01-24T18:45:54Z

Kitz: Created page with " == DACS - Digital Access Carrier System. == A system used by BT circa 1980 - 2000 to provide a telephone service to a premise where there was no spare copper pair availabl..."

2012-01-24T13:28:53Z

Created page with " == DACS - Digital Access Carrier System. == A system used by BT circa 1980 - 2000 to provide a telephone service to a premise where there was no spare copper pair availabl..."

New page

== DACS - Digital Access Carrier System. ==

A system used by BT circa 1980 - 2000 to provide a telephone service to a premise where there was no spare copper pair available.

DACS allows 2 digital telephone signals to be carried over the same pair in the local loop.

== DACS Exchange Equipment. ==

[[File:Dacs_EU.jpg|200px|thumb|right|DACS Exchange Unit]]

<br />DACS works by converting the telephone analogue signals into digital signals and allowing 2 digital signals to be carried over the same copper pair from the exchange to the local pole or in the home.

To the right is a photograph of a typical DACs exchange unit which connects the analogue line from the line card in the exchange and converts the signal into digital format.

The DACS EU also monitors for line faults.

== DACS Remote Unit ==

← Older revision		Revision as of 08:35, 18 May 2024
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	--[[User:Kitz\|Kitz]] 18:45, 24 January 2012 (GMT)		--[[User:Kitz\|Kitz]] 18:45, 24 January 2012 (GMT)
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-A system used by BT circa 1980 - 2000+ to provide a telephone service to a premise where there was no spare copper pair available.
+A system used by BT circa late 1980's - 2000+ to provide a telephone service to a premise where there was no spare copper pair available.
 Copper had become a costly resource and laying new cables to new or remote locations could be very expensive.
 DACS allows for 2 digital telephone signals to be carried over the same copper pair in the local loop.  It was used on exchanges which ran System X and System Y equipment and allowed each telephone line to run independently, unlike the previous 'party lines' where conversations could be overheard and only one subscriber could use the line at any one time.
@@ Line 30: / Line 32: @@
-At the exchange end normal analogue telephone lines are connected to the DACS unit.  The DACS EU then takes any analogue signals from these lines, converts them to digital format and then is able to simultaneously digitally pass information from 2 lines over one copper pair in the local loop.
+At the exchange end normal analogue telephone lines are connected to the DACS unit.  The DACS EU then takes any analogue signals from these lines, converts them to a single 128kb digital format and then is able to simultaneously digitally pass information from 2 lines over one copper pair in the local loop.
 To the right is a photograph of an [http://www.ecitele.com/Pages/Default.aspx ECI] rack which has 15 line cards.  Each card on the rack contains 2 digital trunks for 4 telephone lines, therefore supporting a total of up to 60 subscriber phone lines.
@@ Line 49: / Line 51: @@
 *'''External Remote Units'''
-Commonly used when there was a shortage of available copper pairs in a particular area and for converting lines in to neighbouring properties.  The boxes are black or dark grey and usually located at the top the nearest telephone pole or may be attached to an external wall of the properties
+Commonly used when there was a shortage of available copper pairs in a particular area and for converting lines in to neighbouring properties.  The boxes are black or dark grey and usually located at the top the nearest telephone pole or may be attached to an external wall of the properties.  A similar external unit is also provided for underground which has a re-enforced plastic case.
 *'''Internal Remote Units'''
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 |}
 --[[User:Kitz|Kitz]] 18:45, 24 January 2012 (GMT)

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 At the exchange end normal analogue telephone lines are connected to the DACS unit.  The DACS EU then takes any analogue signals from these lines, converts them to digital format and then is able to simultaneously digitally pass information from 2 lines over one copper pair in the local loop.
-To the right is a photograph of an [http://www.ecitele.com/Pages/Default.aspx ECI] rack which has 15 cards.  Each card on the rack contains 2 digital trunks for 4 telephone lines, therefore supporting a total of up to 60 subscriber phone lines.
+To the right is a photograph of an [http://www.ecitele.com/Pages/Default.aspx ECI] rack which has 15 line cards.  Each card on the rack contains 2 digital trunks for 4 telephone lines, therefore supporting a total of up to 60 subscriber phone lines.
-BT also use [http://www.telspec.co.uk/ Telspec] DACS EU's.  These comprise of 8 Analogue Line Cards and 8 Digital Line cards supporting up to 40 digital trunks/80 subscriber lines
+BT also use [http://www.telspec.co.uk/ Telspec] DACS EU's.  These comprise of eight pairs of line cards (8 Analogue Line Cards + 8 Digital Line cards) supporting up to 40 digital trunks/80 subscriber lines.

@@ Line 1: / Line 1: @@
-A system used by BT circa 1980 - 2000 to provide a telephone service to a premise where there was no spare copper pair available.
+A system used by BT circa 1980 - 2000+ to provide a telephone service to a premise where there was no spare copper pair available.
-DACS allows 2 digital telephone signals to be carried over the same pair in the local loop.
+DACS allows for 2 digital telephone signals to be carried over the same copper pair in the local loop.  It was used on exchanges which ran System X and System Y equipment and allowed each telephone line to run independently, unlike the previous 'party lines' where conversations could be overheard and only one subscriber could use the line at any one time.
 [[File:Dacs_EU.jpg|200px|thumb|right|DACS Exchange Unit]]
-To the right is a photograph of a typical DACs exchange unit which connects the analogue line from the line card in the exchange and converts the signal into digital format.
+At the exchange end normal analogue telephone lines are connected to the DACS unit.  The DACS EU then takes any analogue signals from these lines, converts them to digital format and then is able to simultaneously digitally pass information from 2 lines over one copper pair in the local loop.
-The DACS EU also monitors for line faults.
+|}
-== DACS Remote Unit ==
+--[[User:Kitz|Kitz]] 18:45, 24 January 2012 (GMT)