Bell System Plant Series Manual

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BELL SYSTEM PRACTICES
Plant Series
SECTION 362-010-100
Issue 4, March, 1964
AT&TCo Standard
TYPE N 1 CARRIER TELEPHONE SYSTEM
GENERAL INFORMATION- DESCRIPTION -OVER-ALL SYSTEM
CONTENTS
PAGE
1. GENERAL . .
1
2. TERMINAL TRANSMISSION FEATURES .
7
A.
General
.
.
.
. .
.
7
B. Channel Units
7
c.
Group Units .
10
3. REPEATER TRANSMISSION FEATURES
10
A. General
.
10
B. Frequency Fragging
11
c.
Equalization
11
4.
SYSTEM TRANSMISSION FEATURES.
.
12
A. Attenuation .
12
B. Levels
12
c.
Regulation
.
13
D.
Transmission Performance
15
5. POWER SUPPLY .
.
15
6. SYSTEM EQUIPMENT FEATURES .
16
7. MAINTENANCE FEATURES
17
A.
Testing Arrangements
17
B.
Order Wire and Alarm Circuit •
18
1. GENERAL
1.01
This section describes the general features
of the Type N1 Carrier Telephone System.
Issue 4 of this section replaces Issue 3 dated
January 1961. Since this issue constitutes a
general revision, arrows normally used to indicate
changes have been omitted.
1.02
Descriptive information on the various
equipment components of the system is
covered in the following Plant Series Sections :
362-010-150- Order Wire and Alarm Facili-
ties
362-011-105- Channel Units and Terminal
Mounting
362-011-110- Transmitting and Receiving
Group Units
362-400-100- Electron Tube Repeaters
362-400-120- Low-High Transistorized Re-
peaters
362-400-121- High-Low Transistorized Re-
peaters.
1.03
The N1 carrier telephone system is a
12-channel system designed for short-haul
use on toll and exchange plant cables. The system
employs double sideband carrier transmission on
nonloaded aerial or underground cable pairs. It
operates on a 4-wire basis using two different
frequency ranges and separate cable pairs for
the two directions of transmission. Fig. 1 shows
a simplified over-all schematic of the N1 system.
1.04
Arrangements are provided for 13 channel
frequencies. For most installations,
12 channels numbered 2 through 13 are used.
These 12 channels use the low-frequency band of
36 to 132 kc with carriers at 8-kc intervals for
one direction of transmission. For the other di-
rection, the high-frequency band of 172 to 268 kc
is used. Channel 1 is available for use in place
of any other channel in the system which may be
unsatisfactory due to radio or other interference.
Channel 1 occupies the low-frequency band of
132 to 140 kc and the high-frequency band of
164 to 172 kc. However, channel 13 as compared
to channel 1, provides better transmission per-
formance, especially on long systems.
1.05
The principal parts of the system are the
channel units, the transmitting and re-
ceiving group units, and the repeaters. The
channel units consist of the voice frequency
terminal circuits, the signaling circuits, and the
@ American Telephone and Telegraph Company, 1964
Printed in U.S.A.
Page 1