ENGINEERING INSTRUCTIONS
TELEPHONES
P.B.X.s
B 1080
Issue 1, 5.12.38
PRIVATE MANUAL BRANCH EXCHANGES
Details of Switchboards AT 1810, AT 3718 and CB 887
1. General
This Instruction describes the details of, and the facilities provided by, "Switchboards,
AT 1810, AT 3718
and CB 887," which are floor-type
double-cord switchboards designed for use on the systems shown in Table 1.
TABLE 1
|
Switchboard |
System for which designed |
|
AT 1810 |
Automatic |
|
AT 3718 |
C.B. (manual) and automatic |
|
CB 887 |
C.B. (manual) |
2. Supersession
These switchboards are now obsolescent and are superseded for new work by "Switchboards,
AT 3796" (see B 1030).
3. Equipment, capacity, dimensions, and weights
Table 2 gives the
equipment and capacity for the several existing sizes of each switchboard, and Table 3 the dimensions and weight.
4. Wiring
The wiring of the
switchboards is complete for the capacity quoted in Table 2, except in the case
of the 10 + 60 (180) sizes, in which
extension wiring is only provided for 120 circuits. Wood
spacing-strips occupy the
unequipped indicator and jack positions.
TABLE 2
EQUIPMENT AND CAPACITY OF SWITCHBOARDS, AT 1810, AT 3718 AND
CB 887
|
Type |
Size |
Exch line |
Exch Line Equip |
Extn |
Extn Equip |
Cord cct Capacity |
Cord cct Equip |
|
AT 1810 |
10+30 (60) |
10 |
10 |
50 |
30 |
15 |
11 |
|
AT 3718 |
10+30 (65) |
15 |
10 |
50 |
30 |
15 |
11 |
|
CB 887 |
10+30 (65) |
15 |
10 |
50 |
30 |
15 |
11 |
|
AT 1810 |
10+50 (60) |
10 |
10 |
50 |
50 |
15 |
15 |
|
AT 3718 |
10+50 (65) |
15 |
10 |
50 |
50 |
15 |
15 |
|
CB 887 |
10+50 (65) |
15 |
10 |
50 |
50 |
15 |
15 |
|
AT 3718 |
10+60 (180) |
20 |
10 |
160 |
60 |
18 |
15 |
|
CB 887 |
10+60 (180) |
20 |
10 |
160 |
60 |
18 |
15 |
TABLE 3
DIMENSIONS AND WEIGHTS
|
Type |
Size |
Height |
Width |
Depth overall |
Approx. weight (lb.) |
|
AT 1810 |
10+30 (60) |
4' 7" |
2' 3.5" |
2' 2.5" |
280 |
|
AT 1810 |
10+50 (60) |
4' 7" |
2' 3.5" |
2' 2.5" |
309 |
|
AT 3718 |
10+30 (65) |
4' 7" |
2' 1" |
2' 2.5" |
280 |
|
AT 3718 |
10+50 (65) |
4' 7" |
2' 1" |
2' 2.5" |
309 |
|
AT 3718 |
10+60 (180) |
5' 1" |
2' 2" |
2' 6.5" |
336 |
|
CB 887 |
10+30 (65) |
4' 7.5" |
2' 3.5" |
2' 2.5" |
280 |
|
CB 887 |
10+50 (65) |
4' 7 |
2' 3.5 " |
2' 2.5" |
309 |
|
CB 887 |
10+60 (180) |
5' 1" |
2' 6.5 " |
2' 4" |
336 |
5. Diagrams
The diagrams relating to the switchboards are in the N series.
6. Transmission data
The maximum permissible resistance for exchange line
plus extension is given ,in the following E.I.s:-
TRANSMISSION, Telephone,
B 3503 C.B. manual and automatic areas
B 3504 C.B. manual and automatic areas (divided cord-circuits)
B 3505 L.B. telephone in C.B. manual and automatic areas
B 3550/1 L.B. exchange areas
B 3590 Inter-switchboard extensions.
7. Design and equipment
The design and equipment of these switchboards is similar to that of TELEPHONES P.B.X.s B 1080
(a) "Switchboard, AT3718"
The circuit arrangements do not permit the use of a " Keysender No. 5..." without modification to the board.(b) " Switchboard, AT 1810."
The exchange holding and through-clearing arrangements, also the dialling keys, are in the terminations of the exchange lines instead of in the cord circuits. The dialling keys, one per exchange line, are fitted in the face of the switchboard above the exchange line indicators.(c) " Switchboard, CB 887."
As for " Switchboard, AT 1810," but without dialling keys or dial.
8. Power-supply data
All the above switchboards are run on 12 volts DC.
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Last revised: June 01, 2004
FM