TRAFFIC CONTROL TELEPHONE SYSTEMS Circuit - Sam Hallas

CONTENTS
Part Title Page
1 Key System, Circuit Description ......................................................... 4
2 Selector Key, 4001-A ........................................................................... 17
3 Selector, 4304-A and 4301-A ............................................................ 24
4 Selector Test Set, 4001-B .................................................................. 35
5 Dial System, Circuit Description ....................................................... 39
6 Line Construction and Line Voltage Curves .................................. 50
7 Line Test Set, LU.3101 ...................................................................... 53
8 Relays, Adjustment of .......................................................................... 64
9 Line Switch, 4120 Type ..................................................................... 73
10 Line Switch, 4150 Type ..................................................................... 78
11 Adjusting Tools..................................................................................... 84
LIST OF ILLUSTRATIONS
Figure Title Page
1 General Schematic Key Sending System ............................ (facing) 8
2 Selector Circuit operated through a No. 341-A or
AAJ 4100-1 Transformer ............................................................... 12
3 Selector Circuit operated through 2 Q.4104-1 or 2 No. 70A
Repeating Coils in Series ................................................................ 12
4 Branch Line operated through Repeating Coil .............................. 13
5 Intermediate Telegraph Station . ..................................................... 13
6 Selector Key Case (Capacity 40 Keys) ............................................ 17
7 Selector Key, illustrating method of coding ................................... 18
8 Selector Key, 4001-A ........................................................................... 21
9 Selector 4304-A .................................................................................... 24
10 Selector 4301-A exploded views........................................................ 32
10a Selector 4304-A exploded views........................................................ 34
11 Selector Test Set, 4001-B ................................................................... 35
12 Selector Test Set, Schematic .............................................................. 37
13 Dial System, Schematic .......................................................(facing) 84
14 Line-Voltage Curves-direct signalling............................................... 51
15 Line-Voltage Curves-signalling through one transformer ............ 52
16 Line-Voltage Curves-signalling through two Repeating ....................
Coils ......................................................................................................... 52
17 The Line Test Set ................................................................................. 53
18 Line Test Set-Battery Voltage Test, Schematic . ........................... 55
19 Line Test Set, Resistance by Wheatstone Bridge Test, .....................
Schematic................................................................................................ 56
20 Line Test Set, Earth Fault by Murray Earth Test, Schematic .... 5 8
21 Line Test Set, Resistance by Voltmeter Test, Schematic ............. 5 9
22 Line Test Set, Volts, Resistance Curves .......................................... 60
23 Line Test Set, Selector Circuit Impulse Ratio Test, Schematic.. 61
24 Line Test Set, Reduced Voltage Test for 4301-A and 4304-A .........
Selectors Schematic .............................................................................. 62
25 Line Test Set, Telephone and Ringing Circuit, Schematic .......... 6 3
26 The B.P.O. type Relay ........................................................................ 65
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