GENERAL DESCRIPTION
After the cable laying operations are completed & cables are commissioned into service, all the relevant drawings should be prepared and incorporated in the existing drawings. While preparing the drawing, it is preferable to have certain fixed reference points which normally do not alter their positions without the knowledge of drawing section such fixed points are cabinets, pillars, pressure testing points pillars, Route and Joint indicators , DPs etc.
The following diagrams are to be prepared a) Route Index diagrams of cables.
b) Offset drawings of all the joints mentioned in route Index diagram with reference to fixed reference points.
c) For junction cables offset drawing of loading coil location & joints.
d) Offset drawing of main leading in joint outside the exchange
e) Pillar and cabinet face panel drawing showing the allocations of pairs.
f) Offset drawings of the cabinet & pillar joints.
g) For distribution cables, offset drawings of straight joints, pot head joints and LI cable joint of building.
h) The area maps, block maps, pillar maps & route index cable maps for entire exchange area should also be updated and incorporated.
In addition to this relevant cards should be prepared entering all the details as required in cards. The important cards are MDF cards, cabinet pillar cards and DP cards.
EXTERNAL PLANT
RECORDS:-(a) Numbering schemes of cabinet / pillar / DP
i) Cabinets are given two digits number in the series 01 to 20 Pillars are also given two digits numbers but in the series 21 to 99 . It is not expected that the number of cabinets in one exchange area will exceeds 20 or pillars exceeds 79. Once the number is given to the Pillar it must not be changed unless it is transferred to another exchange area.
ii) DPs are given four digit number. The first two digits corresponds to the number of pillar from which the DP is fed. In case of Inner zone DP the first two digit will be 00,. The last two digits denote the serial number of DP with the pillar area or the inner zone.
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fuse strips are numbered serially in single digit 0 to 9 . The terminal tags on fuse strip are numbered serially in two digit series 01 to 40, Thus 148/06 refers to terminal 6 of 8th fuse strip on vertical 14.
(c) Terminal code for cabinets/pillars.
The coding of terminal in the cabinet/pillar is fully specified by the number of cabinet/pillar and the position of CT box. In order to specify the position of a CT box in cabinet/pillar, each horizontal row on the panel in assigned a single letter code A,B, C,D,E,F,G etc. commencing from topmost row.
Each horizontal row is divided into section corresponding to 50 pairs each. The 300, 500 & 700 pair shells will have two section per row and 1000 and 1400 shells will have 4 section per row. The sections are numbered 1,2,3,4 commencing from left hand side. 50 pair CT box will occupy one section and its position in particular row is specified by the number assigned to that section A 100 pr CT box occupy two section & its position in the row is specified by the number assigned to Left Hand section. Thus 06 C2/38 refer terminal 38 of 50 pr CT box occupying second section in third row of cabinet 06.
(d) Terminal code for DPs
The position of a terminal on DP is fully specified by the DP number and the terminal number on DP.
Thus 4306/05 refer terminal number 5 of DP 06 controlled by pillar 43. If DP consist of distribution frame work as in case of large building then vertical number is denoted by single digit (0-9) &
terminal number is denoted in two digit ( 00 to 99), Thus 36th tag no the 2nd vertical of DP 4813 will be coded as 4813/236. A detailed example is shown at the end of the chapter for scientific numbering of DPs properly depending on the pars in CT BOX termination.
(e) Coding of primary ,secondary & Distribution cables.
Primary cable is given a single letter code A,B,C,D... etc. the letter I&O omitted, If there are more than 24 cables a two letter code for example AA, AB, AC,...etc. are used. For example C cable is 3rd primary cable & AB cable is 26th primary cable.
Secondary cable is coded with the cabinet number followed by single letter A,B,C,D,...etc. for example 12 C is third secondary cable original from cabinet. 12.
Distribution cable is coded with the pillar number followed by single letter A, B, C, D,.etc. for example 43 F is 6th distribution cable originated from pillar 43.
(f) Coding of Junction cable
Each exchange is assigned a letter preferable first letter of exchange name. For example C for city exchange P for park exchange. The junction cable code will consists of two letters denoting the exchanges at which the cable is terminated and digit denotes the serial number amongst the cable terminated between these exchanges. For example junction cable between city & park exchanges are coded as CP 1, CP2 CP3...etc.
(g) Coding of cable pairs
Cable pair are designated by the cable code followed by the pair number within that cable for example pair 86 of cable 50 A will be coded as 50A/86.
CARDS ( shown at the end of chapter ) (a) The DP Cards
DP cards shows the number, size type, location and how each terminal of DP is utilized, they also indicate the distant end terminal code corresponding to each terminal of the DP . One card is required for each 10 or 20 pair DP. For DPs larger than 20 pairs two or more cards have to be used.
Terminal 1 to 10 details are prepared in the obverse &^ 11 to 20 in the reverse of DP card.
These cards must be introduced soon after the scheme for changeover to cabinet and pillar area system is finalized & DPs are assigned numbers in the new series. there after the card must be kept updated by incorporating all additions and alternations effecting the particulars contained in the cards.
(b) Cabinet / pillar cards.
One set of cards is required for each cabinet/ pillar. the set contains one card for each 50 pr CT box fitted in cabinet /pillar.
The following particulars are shown on each card. Number, size type of CT box , size of shell location of cabinet/pillar, circuit working on each terminal of CT box, terminal to which it is jumpered or strapped for setting up the circuit, the distant end terminal code corresponding to each terminal of the CT box and the code of cable pairs connected to the terminal. Obverse maintained terminal 1 to 50 of G box & Reverse is for terminal 51 to 100 . The same card can be used for cabinets as well as pillars. these cards must be filled in at the time of installation of each cabinet or pillar and subsequently addition or alteration effecting the entries must be incorporated in the corresponding cards.
(c) MDF CARDS
MDF cards contain following particulars. Distant end terminal code corresponding to each terminal on fuse strip, circuit number working on that terminal, address of the subscriber. One card is required for each fuse strip. entries for tag 1-10 are made on obverse & tag 11 to 20 on the reverse of the card.
If junction cable pairs are terminated on fuse strip, the terminal code at the MDF of the other exchange is entered in column 2 . The name of other exchange is entered at the top of the card. In the last two column. Junction circuit number and the exchange between which it works respectively.
For miscellaneous circuit subscriber address should be entered in the last column. The MDF cards must be introduced after the DPs are assigned number in the new series.
(d) Subscriber Index Card.
The subscriber Index card is maintained to get the particulars for the termination’s of subs lines. the terminals particulars circuit wise can be easily ascertained from this card. There are two types of cards required for this purpose. One is for Direct exchange lines & other for non exchange lines.
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SUBSCRIBER INDEX CARD Subs
NO
MDF CABINET PILLAR D.P.
F.S. Term No E.side D.side No E.side D.side No Term ADDRESS 0 1/3/4 06 06 B1/01 C1/51 47 B1/51 C2/12 4
741 2 ABK Rao
Station Rd 1
2 3 4 5 6 7 8 9