How To Find Your MDF Position From Your Equipment Number 

Researched and Written by iNFERNO 
How to find you MDF position from your Equiptment Number | iNFERNO 1996 

A subscriber's line can be identified within a concentrator by the number 
of the equiptment to which it is connected. The equiptment number is within 
the range 0-2047 for each concentrator, if there is more than one 
concentrator within the exchange the the equiptment numbers expand in 
multiples of 2048. 

The shelves in the T.E containing the groups of Subscriber Line Units 
(SLUs) are labeled ALUS xx yy, where xx is the concentrator No. and yy is 
the shelf group No. within that concentrator. The MDF blocks are 
similarly marked. 

To determine the MDF block and circuit No. of a subscribers line, given 
the Equiptment & Concentrator No. : 

o Divide your EN by 2048, which gives a number and a remainder. The 
remainder is the Subs Line No. within that concentrator. 
o Dividing the remainder by 192 gives the Shelf Group No. and a new 
new remainder. This remainder gives the Circuit no. in that shelf 
group. 

e.g Concentrator 3, EN 10720: 10720/2048 = 5.480.. Line No. 480 in Conc 3. 
480/192 = 2.96, giving ALUS 3-2, Circuit 96. 

o For Mark 2 SLUs: Divide the circuit No. by 8 to give the SLU No. 
o For Mark 3 Plessey SLUs: As above, but if the remainder is odd then 
add one too the SLU No. 
o For Mark 3 GEC SLUs: Divide the circuit No. by 16 to give the SLU. 

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