| 摘要 |
1318316 Automatic exchange systems; metering PLESSEY CO Ltd 14 Oct 1971 [20 Nov 1970] 55410/70 Heading H4K Periodic operation of a subscriber's meter is effected by a 6-stage binary counter F which is associated with a gating circuit E and is controlled via control circuit A by interlaced recurrent XP, YP, ZP pulses trains each having a pulse interval of e.g. 750 ms, and by pulses RP having an interval dependent on the rate for the call e.g. 18 seconds, one metering pulse being delivered upon the reply of the called party and thereafter in the time interval following every RP pulses, i.e. after the 11th, 21st, 31st RP pulse. Initiation of call.-When the circuit is idle all bi-stable devices are in the "0" state and the counter F is at the X11 or home stage. The XP, YP, ZP pulse trains are continuously applied but have no effect, the XP train being associated with exclusive subscriber lines and X- part lines, and the YP pulses with Y-party lines. When a subscriber has dialled, an RP pulse train corresponding to the call rate is applied to control circuit A and a corresponding wire X or Y is marked in phasing circuit B, causing a and b pulse trains to be generated, the b train being in phase with XP pulses if wire X was marked or YP pulses if wire Y was marked. The converse applies to the a train. When the called subscriber replies wire SA is marked in delay circuit C. On the next XP, YP or ZP pulse a respective bistable BC1-BC3 switches to the "1" state. Two pulses later, i.e., if the first pulse was an XP pulse, at the time of occurrence of the next ZP pulse, bi-stable BC4 is switched to the "1" state marking a wire SB. Marks SA and SB are then maintained throughout the call mark SA inhibiting a gate GD1 in part D thereby keeping bi-stable BD1 in the "0" state. On the first a pulse after wire SB is marked, bistable BE1 is switched to the "1" state. At the next b pulse gate GE7 is opened, a metering pulse is supplied over lead M and a bi-stable BE2 is switched to the "1" state where it holds until the end of the call. The next a pulse resets bi-stable BE1 to "0". Further a and b pulses are ineffective until the next RP pulse arrives opening gate GA1 thereby switching bi-stable BA1 to the "1" state. On the next b pulse gate GA7 opens and bi-stable BA3 switches to "1". The following a pulse opens gate GA11 and an odd drive pulse is delivered on device 1 which; switches the counter to position one; sets bistable BA4 to "1"; and sets bi-stable BA1 to "0". The following b pulse resets bi-stable BA3 to "0". Following a and b pulses are ineffective until the next RP pulse arrives switching bistable BA1 to "1". The next b pulse resets bi-stable BA2 to "1". The next a pulse causes an even pulse to be delivered on wire 2, and the counter switches to position two; the pulse on wire 2 resets bi-stables BA4 and BA1 to "0". The next b pulse resets bi-stable BA2 to "0". The process repeats until the counter reaches position ten and gate GA12 is marked When the next RP pulse arrives, i.e., the eleventh and therefore an "odd" pulse, bi-stable BA4 is not operated because gate GA12 is held open, but the counter moves to position eleven, i.e., the metering position. Continuation marks are then applied to gates GE4, GE6, GE8, GD2, GA12 and GE2, GE2 being inhibited by the application of the mark. At the next a pulse following the application of the continuation marks. bi-stable BE1 switches, to "1", gate GE8 opens and a continuation signal arrives at gate GA3 switching bi-stable BA1 to "1". At the following b pulse GE7 opens and a metering pulse M is delivered which also switches bi-stable BFF in the counter to "0" thereby switching the counter to position twelve. This b pulse also opens gate GA7 switching bi-stable BA3 to "1". On the following a pulse bi-stable BE1 holds at "1"; gate G1A1 is opened to deliver a re-cycle drive pulse to odd lead 1, thereby switching the counter to position one. Bi-stable BA4 switches to "1" and bi-stable BA1 to "0". On the next b pulse bistable BA3 resets to "0" and on the following a pulse bi-stable BE1 is switched to "0". The cycle then repeats for further time intervals. Termination of call.-If the calling subscriber hangs up a reset signal R is applied to all bistables, switching them to the "0" state. If the called subscriber on-hooks before the calling subscriber mark SA disappears and the inhibit is removed from gate GD1. When next the counter reaches the metering position the meter pulse M switches bi-stable BD1 to "1". When the counter moves to position twelve, the home position, gate GD2 does not open. If the caller has not hung up by the time the counter next reaches position eleven, gate GD2 opens holding bi-stable BE1 at "0", and no further metering pulses are delivered. Party line metering.-The metering pulse M is always delivered at the time of a b pulse. As the b pulses are phased with the XP or YP pulses according to which wire W, Y was marked it is possible to provide for separate metering of two party lines. No further details are given. Circuitry.-A circuit employing MOST's which performs the logic functions of Fig. 1, is described with respect to Fig. 4-7 (not shown), several gates and bi-stables being combined in order to reduce the number of MOST's. The circuit may be integrated on one or more chips and in this respect Specification 1,311,342 is referred to. |
