Patent GB-693849-A (GB)
Title: Improvements in or relating to credit sanction systems
Inventor: KING JOHN ARTHUR BARFIELD
IPC: G07F7/08
Filed: 1950-11-15
Abstract: 693,849. Credit sanction systems. STANDARD TELEPHONES & CABLES, Ltd. Nov. 9, 1951 [Nov. 15, 1950], No. 27953/50. Class 40 (iv). [Also in Group XVIII] In a credit sanction system, a switch acts as a line-finder in calls from a salesman to an authorization position and as a selector in a call in the opposite direction. According to whether the call is to authorization position 1, 2 or 3, a salesman depresses no button or button APB or APC. When the salesman closes his loop, L operates to energize pilot relay P and mark the appropriate contact in bank lf5. P lights a call lamp at the authorization position, Fig. 3, and energizes call buzzer BZ. When the authorization clerk lifts his receiver, D pulls up to energize BB, Fig. 2B, to operate ST. ST connects FT to wiper lf5 and causes magnet LF to step the line-finder wipers until lf5 finds the calling line when FT pulls up, followed by KK, which locks. KK releases ST to prevent further hunting, operates K and establishes the connection. Relay AA pulls up so that if the salesman has inserted the bill properly in a receptacle, battery on terminal A energizes LL. Relay K restores P and disconnects the calling lamp and buzzer, but if another call is waiting P holds to maintain the lamp. Sanction operation. Operation of LL lights sanction lamp SL. The clerk hears the details of the transaction and if it is permissible he operates sanction key SK to energize SN, which operates LA, and operate the meter M. SN also earths the sanction lead to release LL and punch the bill, the punch magnet removing battery from the A terminal. Release of SK restores SN and KK and all the relays in the line circuit. If a queue exists the clerk does not hang up and the line-finder hunts for. another calling line. Ring-back facility. The clerk can call back the salesman, if the latter has not hung up, by .depressing key RK to energize RB which breaks the line and connects the salesman's line circuit to terminals Al, B1, S1, so operating TG, Fig. 4, which applies ringing tone to the salesman's position while RK is operated. Call from authorization position. The clerk closes his loop and depresses dial button DB to energize OG, so preventing attempted calls by salesmen and driving switch LF to home position under the control of homing bank lf7. CA then operates, locks up, energizes CD and earths terminal S1 to start TG. CA also energizes 1A and 1B. CD connects magnet LF to the impulse circuit, energizes ST and returns dial tone through D to the clerk, who then dials the wanted number, either 2-9 or 01-07. In the case of the single digit, D and magnet LF follow the dialled impulses, CD holding up until the end of the train when it falls back to disconnect the magnet circuit. While ST releases slowly FT pulls up in series with L and K of the selected salesman's position. FT also operates KK which locks up, establishes the speech connection and disconnects the tone circuit. The authorization clerk then depresses the ring key RK. In the case of two digits, the first digit steps the switch ten times, CD being held by the tenth contact of bank lf8. When the switch stops after the second digit, CD releases and connection is made as already described. Line engaged or wrong number dialled. If the salesman's position is engaged, earth from kk3 prevents test relay FT operating while if the called position is not connected absence of battery prevents operation of FT so that KK does not energize. Busy tone is then returned to the authorization clerk.