SECTION 506-3241-200
3. CIRCUIT DESCRIPTION
Coin Signaling
3.01 Coins inserted in the · single slot and
accepted by the chute are sorted into the
appropriate channel before passing through the
coin switch module.
As
the coin passes through the
coin switch module, a switch is activated which in
tum
energizes the solid-state tone generator. The
generator sends bursts
of
tone appropriate
to
the
coin deposited
to
permit operator recognition. The
signal~
are
not
heard in the receiver
of
the coin
telephone set. The number
of
tone bursts for each
coin deposited are:
• one burst for a 5-cent coin
• two bursts for a 10-cent coin
•
five
bursts for a 25-cent coin (transmitted
at
twice the rate
of
the 5-cent and 10-cent
coin tone bursts).
Mechanical Totalizer
3.02 The mechanical totalizer detects the total
number
of
5-cent coins deposited for
10-cent initial rate calls.
3.03 The first 5-cent coin,when passing through
the coin switch module, operates the
totalizer and drops in the coin hopper,tripping the
coin trigger. When tqe second 5-cent coin
is
deposited the mechanical totalizer permits dialing
from the coin telephone set. The operated hopper
trigger switch provides ground on
the
CO line
to
collect/return the deposited coins and
to
request
service on ground startline circuits.
3.04 A deposited 10-cent coin
or
25-cent coin
is
segregated by the coin chute and passes
through the coin switch module. The tone
generator monitors the switches
on
the switch
module and generates the appropriate coin signals.
The coin then drops into the coin hopper, tripping
the hopper trigger which allows the ca
ll
to
proceed.
The mechanical totalizer
is
not
operated by the
deposit
of
these coins.
Page4
Electronic Totalizer (VIR)
3.05 The electronic totalizer
is
used
to
inhibit
dialing (or continuity
to
ground for FASN
operation) in the same manner
as
the mechanical
totalizer. The electronic totalizer receives its input
signals from the same switches on the switch
module which provide inputs
to
the
coin signal
tone generator. The electronic totalizer can be
strapped (on the
PCB
assembly) so
that
it
enables
dialing (or continuity
to
ground for F
ASN
operation) when the total value
of
the coins
deposited equals
or
exceeds the preset initial rate.
The initial rate may be preset by appropriate
strapped connections on the
PCB
assembly.
F
ASN
Operation
3.06
When
the coin telephone set is used with a
CO
which
is
equipp.ed
to
provide F
ASN
service the user receives dial tone by lifting the
handset and may complete a call
to
any free access
number without depositing coins.
3.07
When
a non-FASN call
is
made, ground
identification is detected by the
CO
when
the initial rate
is
deposited.
GI Feature
3.08 The GI feature provides a means
of
disconnecting the station ground from the
transmission network whenever line current
is
flowing. This feature achieves a substantial
reduction in transmission circuit noise caused by
induced voltages on
th
e line.
3.09
GI
is activated by current on the ring side
of
the line.
When
this feature is used, ground
tests
or
coin collect/return functions, which
require an electrical continuity
to
ground, must be
made on the tip side
of
the line only.
Coin Rejection
3.10 Slugs, washers, tokens, or foreign coins
inserted through the slot in the coin guide
are directed
to
the coin chute and rejected
to
the
coin return assembly
or
held up. The coin return
