Patent GB-199509-A (GB)
Abstract: 199,509. Western Electric Co., Ltd., and Polinkowsky, L. March 31, 1922. Semi-automatic exchange systems.- In a system in which calls arriving at a manual exchange from an automatic exchange are stored in register-sets and thence transferred to a number indicator, upon a trunk being seized again before the release of the called line, the wanted number is registered but is not displayed until the first connection is released, indication being given to the operator by a supervisory lamp normally controlled by the called subscriber. Means are provided for marking all the trunks busy at the automatic exchange when two (or more) calls are waiting before the operator, and for restoring the apparatus if a call is given up before the wanted number is indicated. Each register-set comprises trunk-finders TF<1>, TF<2>, registers THR, HR, TR, UR with a control switch CS and indicating lamps. The register switches have 20 terminals each, being arranged to re-translate non- decimal records at the automatic exchange to the original decimal numbers. Operation of trunk-finder to connect registerset to the calling trunk. The operation of the line relay 3 upon seizure of the trunk 1, 2 energizes a relay 4 which connects up the calling lamp CL through a resistance 7 causing a dim glow, operates a relay 8 which completes driving circuits for the trunk-finders TF<1>, TF<2>, and connects a. relay 18 to the contact in the bank 14 representing the trunk. When this contact is reached by either of the trunk-finders, the relay 18 energizes in series with a test relay 21, which connects a relay 11 in series with the stepping magnet 9, which then no longer operates. The relay 18 locks itself and the relay 52 which was energized by the relay 4, and opens the trunk 1, 2, releasing in turn the line relay 3, relays 4, 8 and the motor magnet of the remaining trunkfinder. The relay 11 energizes and operates a relay 24 which connects the wipers 15, 16, 17 of the trunk-finder to the registering mechanism, and a relay 10 which releases the test relay 21 and the motor magnet 9. Transfer of wanted number to register-set. The relay 10 also operates relays 200, 201 in turn, whereupon relays 204, 210 are connected to the fundamental circuit through the register-set at the outgoing exchange. When this circuit is closed, these relays energize, and operate a relay 212 which connects up the stepping magnet 220 of the control switch CS. The relay 204 also releases in turn the slow relay 200, relays 201, 212 and the magnet 220, so that the switch CS is moved one step, bringing the thousands register THR into operation. A relay 226 energized by the relay 204 and the stepping magnet 205 now interact to send reverting impulses over an earthed front contact of the relay 226 to the stepping magnet of the register at the outgoing exchange until the latter is in normal position, when the fundamental circuit is broken, releasing relays 204, 210, 226 and the magnet 205. The register THR is now set according to the first digit. The registers HR, TR, UR are set in a similar manner. In the case of the units register UR moving into the second half of its bank, a relay 282 is provided to prevent release of the relay 226 in passing over the normal contact 281. The circuit of a lamp to indicate the ten thousand digit, that is, the level of the selector at the outgoing exchange, may be prepared in the bank 17 of the trunk-finder. Upon the release of the relay 204, a relay 211 is energized, bridging a relay 235 across the trunk and bringing into operation a timing apparatus CTA, described below. Transfer of wanted number to lamp indicator. When the registering mechanism at the outgoing exchange is released and the sequence switch of the cord circuit moves to the talking position, the relay 235 operates, disconnecting the timing apparatus CTA and energizing in turn relays 236. 202, 241, the last of which lights the selected lamps, the circuits of which are shown at the bottom of Fig. 2. The relay 202 connects up an interrupter device CIM to the lamp CL, causing it to flicker. Extension of call by operator. Upon plugging into the jack of the wanted line, relays 40, 6, 51, 55 are energized in turn, removing battery and earth from and swatching through the trunk conductors 1, 2, the relay 55 being locked by the energization of the line relay 3. The relay 55 also releases the relays 18, 21. The relay 18 releases a relay 52 energized when the cord circuit was taken into use, operating the ringing relay 60 through a relay 53 and a hot-wire relay 57, which brings a hot-wire relay 58 into circuit, energizing a relay 54, which short-circuits the ringing relay 60 and releases the relay 51 which completes the through connection. A relay 50 operates on .the reply of the called subscriber and extinguishes the lamp SL which was lighted by the relay 6. Release of lamp indicator and register-set. The relapse of the relay 21 short-circuits the relay 11 energizing relays 243, 221 in parallel. The relay 243 operates a relay 203, which releases the relay 236, short-circuiting the relay 202, which opencircuits the relay 241, extinguishing the indicating lamps. The relay 221 connects up the stepping magnet 220 of the control switch CS over a self-interrupting circuit, so that the switch moves one step to complete the driving circuit of the thousands register THR, which is rotated to normal position. The magnet 220 is then again energized momentarily, and the registers HR, TR, UR are restored to normal in turn. Release; seizure of trunk before called subscriber hangs up. Hanging up by the calling subscriber causes the lamp CL to glow by the release of a relay 5 in series with a relay 55 upon relapse of the line relay 3. When the called subscriber hangs up, the lamp SL is lighted by the release of the relay 50. If the trunk is taken into use again before the called subscriber hangs up, the number of the wanted line is set up as before on the register-set, but the operate on of the relay 40 prevents the energization of the relay 236 to light the lamps, and the operation of the relay 6 lights the lamp SL. Call distributing. If two waiting calls are received, a marginal relay 70 operates upon energization of relays 4 over parallel circuits containing resistances 71, open-circuiting a distributing relay 74 at the distant exchange, which releases relays 77 rendering all the trunks non-selectable. In the case where the manual exchange is accessible from a number of automatic exchanges, an intermediate relay 80 is provided (the wire being cut where indicated by the cross), which causes the release of a relay 74 at each exchange. Timing apparatus CTA. This effects release if the call is given up before the indicating lamps. are lighted. The relay 235 does not operate, and the relay 211 energizes a relay 260, which connects up a slow relay 261 in series with it, operating the stepping magnet 262. The relays 260, 261 and the magnet 262 interact to rotate the switch in a definite time determined by the slow relay 261 until a circuit is closed for the relays 243, 221 in parallel.