AT&T Bell System F-58654 Description And Operation

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BELL SYSTEM PRACTICES
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TCo Standard
SECTION 107-305- 100
Issue 2, : September 1976
tF-58654 PORT ABLE TEST SET FOR ACOUSTIC
AND INDUCTIVE COUPLERS
DESCRIPTION AND OPERATION.
CONTENTS PAGE
1. GENERAL
2. DESCRIPTION
2
A. Physical Description
2
B. Control Keys and Jacks 2
C. Functional Description 2
3. OPERATION
4
4.
CALIBRATION 5
5. MAINTENANCE 7
6. REFERENCES
7
1. GENERAL
1.01
•This section provides descriptive, calibrative
and operational information for the F-58654
coupler test set, hereafter referred to as the test
set.•
1.02
This section is reissued to correct the title
and a voltage value in the oscillator frequency
check. Calibration information has been arranged
in step procedure format and includes additional
information when using a 600 ohm oscillator.
1.03
The test set is designed to measure the
output level of the signal power for
customer-provided acoustically or inductively coupled
voiceband equipment. Use of the test set will
verify customer compliance with the applicable
tariff in regard to signal power within the bandwidth
of 300-3200 Hz when coupling customer-provided
equipment (CPE) to the direct distance dialing
(DDD) network. Signal levels from CPE must not
exceed -9 dBm at the input to the local loop when
averaged over a 3-second interval. The telephone
company (telco) may authorize a higher input signal
power level on a fixed longer-than-average local
loop in order for the power level input at the
central office (CO) to be approximately -12 dBm
or less (3-second interval average).
1.04
•The test set simulates the transmission
characteristics ·of a 500-type telephone set
when connected to a 900-ohm loop with a 3-dB loss
at 1000 Hz .•
Acoustically Coupled CPE
1.05
A signal acoustically coupled to the DDD
network is influenced by the acoustic interface
between the acoustic device and the telephone set.
In addition, the electrical and acoustic properties
of the telephone set and the characteristics of the
transmission facilities affect acoustic coupling. The
T-type carbon transmitter (which is used in most
500-type, Princess®, and Trimline® telephone sets)
is sensitive to certain factors such as handset
position, vibration, and packing of the carbon
granules in the transmitter.
Inductively Coupled CPE
1.06
Since a telephone set contains components
with magnetic fields associated with them,
inductive coupling of data or voice signals is possible.
One means of inductively transmitting by magnetic
coupling is through a U-type receiver found in most
500:type telephone sets. Trimline and some 500-type
tefephone sets equipped with LA- or LB-type
receivers produce weak magnetic fields, making
inductive coupling impractical.
NOTICE
Not for use or disclosure outside the
Bell System except under written agreement
Printed in U.S.A. Page 1