Functional Description - AT&T Bell System 401E Series Description And Operation

SECT ION 594-014- 100
8 - 3/4
II
TEST KEYS
Fig. 1-Data Set 401E2 or 401E3
When the DlOM-61 cord is used, connections are
made on the terminal block furnished with the cord.
2.04
Interface connections are made through a
KS-19087-L2 connector located at the rear
of the set (Fig. 3). The corresponding plug (Cannon
or Cinch DB-19604-432) and connecting cord must
be provided by the customer.
2.05
A G lB ringer provides an audible signal.
Access to the ringer volume control is
through a hole in the base of the set. If a louder
signal is required, the ringer provided in the data
set should be disconnected and rep~aced with an
external ringer. Type and number of ringers
permissible should be determined by existing BSPs
on ringers, subsets, and ringing bridge limitations.
2.06
Power for the data set is obtained from
the telephone line . There are no internal
fuses in the data set.
Page 2
2.07
The data set is designed to operate within
an ambient temperature range of
+
40 to
+
120°F with a relative humidity of 20 to 95 percent.
3. FUNCTIONAL DESCRIPTION
3.01
The data transmitter circuit consists of three
transistorized oscillators. From each oscillator
circuit in the data transmitter, four data leads
connect to the business machine. An additional
lead which is common to each oscillator connects
to the business machine as a common lead. Data
from the business machine consists of contact
closures between the common lead and one data
lead from each oscillator. Thus, the transmitted
signal for each character consists of a composite
of three frequencies, one from each oscillator.
With the A and B oscillators capable of generating
5 frequencies each and the C oscillator capable of
generating 4 frequencies, a code of 100 combinations
is possible.
3.02
If none of the data leads from an oscillator
is connected with the common lead, that
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