Patent GB-1027464-A (GB)
IPC: H04M17/02
Abstract: 1,027,464. Automatic exchange equipment. ERICSSON TELEPHONES Ltd. Nov. 8, 1963 [Dec. 18, 1962], No. 47849/62. Heading H4K. A coin-box sends signals indicative of the value of inserted calls, the signals being accompanied (either during or immediately after said signals) with a brief loop-break signal, and payment control apparatus in a T.D.M. exchange, assignable to a call from such a box, is arranged to disconnect the call if such a loop break signal is not received. General.-Use is made of a supervisory circuit which is capable of responding to various line conditions pertaining to the call set up or being set up, and distributing corresponding conditions as required. Such conditions may consist of line loop, line open or 5K# loop. Coin insertions are signalled by a plurality of 5K# loop conditions (indicative of the value of the coin) accompanied by a momentarily open loop (either just after the last 5K# pulse or during the last of these pulses). The supervisory carries its information at pulse times indicative of a channel used for the connection. A plurality of CFC's (coin and fee checking equipment) are provided, one of which may be seized by the supervisory when required by inserting a channel pulse in a store in the CFC. Signalling between the supervisory and the CFC (and also between the CFC and other equipments such as pay tone control circuits) occurs during the channel pulse period concerned. In the case of signalling between CFC and supervisory the channel pulses are caused to occur only in other less frequently occurring periods, these periods being used to indicate and identify the nature of the signals. Within the CFC pulses coincident with channel pulses are used for counting purposes. Two master stores in conjunction with an adding circuit are used inter alia for timing purposes. For any given timing operation a pulse is inserted at a channel pulse position p x  and regularly recurring pulses are applied to a binary adder until a pulse appears at p(x+y) which pulse is then detected; y is chosen according to the time to be measured. Different timings are started at different x-values. A free CFC signals the supervisory in specific class of service indicating periods. When the latter requires service it sends a channel pulse for insertion in the store BS of a free CFC. The supervisory also signals whether the substation is a call office or a privately rented call box. When the called subscriber answers the supervisory signals this to the CFC which then causes pay tone to be sent to the calling and called subscribers and signals the supervisory to effect line-split and to unlock the coin-box slots. A timer is then started as indicated above and when 9À5 secs. have elapsed the pay tone is cut-off. After a further two seconds the timer causes the CFC to signal the supervisory to connect NU tone unless coin pulses are received. Arrangements are provided to credit the subscriber with time elapsing between the receipt of the last meter pulse and the insertion of a coin. Thus meter pulses indicated by the supervisory are arranged to initiate a count in the timer, the count being started afresh each time a meter pulse arrives. This count is subsequently increased by further pulses applied during further occurrences of coin pulses. The supervisory signals the CFC according as a 5K# loop or make loop is present, break being deduced from the absence of the other two conditions. The 5K# pulse is timed and if sufficiently persistent is recorded and caused to disconnect pay-tone; the subsequent make period is similarly timed. If an end of train break which is timed in the usual way is not detected within 2 seconds then the CFC signals the supervisory to send NU tone and subsequently release the connection. Each successful 5K# test results in the storage of 1 in complementary form in the master store. Each coin pulse in the case of a call office is signalled to the supervisory for adding to the appropriate meter record. If the line has low insulation then this is recorded in the supervisory during dialling and signalled to the CFC which thereupon when the first meter pulse is received causes the reversion of NU tone and release of the call. In the case of a privately rented callbox record meter signals and not the value of coins in the coin box are recorded in the meter record. To avoid saturating the counter, when the latter indicates that 33 coin units are in credit the CFC signals the supervisory to lock the coin slots. When a meter signal is received the stored credit time is used to derive a complement of this time which is also stored. This complement is then counted out whereupon the stored complement of the coin units is increased by one (i.e. reducing the credit by one). If the call box is pvivately rented then a signal is sent to the supervisory to record the meter unit. If a further meter signal is received before the credit time is counted out then the credit time is erased, and the stored complement is counted out, pulses being correspondingly inserted into the credit time store whereby the credit time is reduced by an amount equal to the interval between meter pulses. The coin units in credit are not affected in this case. When all the credited coin units have been used, pay tone is again sent but line split is not effective this time. The stored credit time is also erased. In the case of privately rented CCB's recording of the last meter signal is suppressed. The pay tone is timed for three seconds after which it is disconnected, but the time continues and after a further seven seconds it emits a further signal, causing looking of the coin slots. Two seconds later the timer causes NU tone to be reverted to the caller and the call to be released. Insertion of further coins during the seven-second interval causes operations to take place as previously described. Credit time is not stored on this occasion in respect of the interval between reconnection of pay tone and insertion of coins. If a meter signal arrives during pay-tone the pay-tone timer is erased and the coin slots locked, and the coin pulse store now shows a debit. If, however, coins are in transit at this time sufficient to put the subscriber in credit the call is allowed to proceed as soon as the coin pulses are received. If several metor units have been stored anticipating payment thereof, metering signals are sent as each meter unit is paid for. Recording of coin pulses takes place irrespective of the credit or dibit position. Call to manual board.-On a call reaching a distant manual board positive battery is signalled back over the junction and the supervisory signals the CFC which performs a persistence test after which it causes line split and pay-tone to be returned to the operator but not to the caller. The operator then operates a key to put a further positive battery on the junction and this removes the line split and pay tone so connecting the operation to the caller. The operation then operates the key again and this time the signal causes the unlocking of the coin slots. Coin pulses are received in the usual way and are repeated to the operator as bursts of NU tone. If no end of train break is obtained NU tone is sent to the operator only and the coin slots are locked. By re-operating the key the operator can disconnect the NU tone and unlock the coin slots. The operator may request audit facilities i.e. ascertain how many coin units the caller has to his credit. The operator operates her key. This " start audit " signal locks the coin slots and prevents addition to the meter record. A stored coin credit which is at present stored in complementary form is registered again. When the operator's key is restored a timer is operated to time a gap of 180 m/sec. followed by the reversion of 90 m/sec. NU tone to the operator, a sequence of such operations occurring the second coin record (complementary) being stepped once each time. The number of signals is counted and at the end of every fourth signal the timing circuit is modified to give a longer break (1À2 secs.) after which the procedure is repeated. The count is thus sent to the operator in blocks of four (as far as the penultimate block). When the counter has been counted out the coin slots are again unlocked. The operator may throw her key during an audit to restart it. In the case of a revertive call from an operator to a coin box, a CFC is automatically connected up and a 3 second tone reverted followed by a timed 9 second period. If the operator throws her key during this period the CFC will remain connected up to provide audit facilities as previously described.