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SECTION 506-4001-290
1. GENERAL
1.01 This manual describes the QSD401A and
QSD240 IA CENTURION semi-postpay,
single coin slot telephone sets. Dismantling and
assembling information is given to facilitate
installation of the coin telephone sets.
1.02 For detailed description, installation,
maintenance, and repair information, refer
to Section 506-4001-200 and 506-4001-500.
2. DESCRIPTION
2.01 The CENTURION coin telephone set type
QSD401A (Fig. 1) is equipped with a rotary
dial, and the type QSD2401A (Fig. 2) is equipped
with a 12-button DIGITONE* dial.
2.02 The CENTURION coin telephone set can be
converted from rotary dialing to
DIGITONE dialing or vice versa, by interchanging
the dial and housing assembly and the hood unit
assembly. The components mountid on the
housing unit assembly are identical for both the
QSD401A and QSD2401A.
2.03 The sets are equipped with an electronic
variable initial rate coin totalizer (VIR) on
the printed circuit board (PCB) assembly. The VIR
totalizer can be modified to increase the initial rate
from 5-cents up to 40-cents in increments of
5-cents.
2.04 The set weighs approximately 50 pounds
(22. 7 kilograms). The overall dimensions are
shown in Fig. 3.
3. SEMI-POSTPAYOPERATION
3.0 l When the handset is lifted off-hook battery
and ground are connected to the set (-48 V
battery to the ring side of the line, ground to the
tip side of the line). Dial tone is heard and dialing
may proceed.
3.02 When the called party answers, the central
office provides battery reversal to the coin
telephone. When the battery polarity is reversed a
*Registered Trademark of Northern Electric
Page 2
diode in series with the transmitter prevents
current from passing through the transmitter. In
this way transmission is prevented.
3.03 Coins must now be deposited to a value
equal to or exceeding the initial rate. The
coin signaling and totalizer circuit, which is
protected by a polarity guard, will respond to the
deposited coins. When the initial rate is reached the
totalizer latching relay (LRT) operates. The
operation of LRT shunts out the diode in series
with the transmitter, thus enabling transmission.
3.04 Battery reversal does not occur on calls to
the operator and transmission is permitted
at all times.
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6.41
Fig. 3 -Rear View of CENTURION
Coin Telephone Set
