621,816. Automatic exchange systems. STANDARD TELEPHONES & CABLES, Ltd., BRAY, F. H., HARTLEY, G. C., and RIDLER, D. S. Oct. 30, 1946, No. 32237. [Class 40 (iv)] Registering and controlling means comprise electric discharge tubes both for separately registering individual digits of a number and for counting out in turn the registered digits. As shown applied to a keysender, successive digits are stored on successive sets of neon tubes, which are then connected to a counting device employing cold cathode discharge tubes to control the emission of trains of impulses. Storage of digits.-Operation of the sender key SK energizes a relay GA to apply operating potential to the circuits. Depression then of a digit key reverses the charges on some or all the condensers C5-C8 according to a code to send charging currents through related resistances Ra-d to fire an appropriate combination in the first set of neon tubes in the storage circuit. Depression of the digit key also energizes storage relay S to operate relay A and therefore relay SJ, which locks and lights the usual sender busy lamp SBL. Release of the digit key releases storage relay S to lock relay A and energize relay B, which transfers the connections of the triggering condensers C5-8 to the second set of neon tubes. Digits are entered thus into successive sets of neon tubes, the locked relay in the series A-H being released at the energization of S and the subsequent relay operating at the relapse of S. At the release of the eighth key, disconnect relay DS energizes to release H. If, however, less than eight digits are to be stored, the start send key is depressed after the last digit key to energize relay H and therefore DS, which releases H as before. Relay DS disconnects the storage circuit from the triggering condensers C5-8 and the relay S from the digit keys. DS also energizes transfer relay TR which locks and connects the storage circuit to the electric counter to control the transmission of the stored digits to line. Electric counter. The energization of relay GA resulting from the original operation of the sender key discharges condenser C16 to fire the odd-numbered tubes in a set of eight coldcathode discharge tubes CT1-8 arranged in pairs on a flip-flop basis to operate on the binary system. The energization of the transfer relay TR now connects the cathodes of the first set of neon tubes to resistances R22-25 to transfer the stored digit to the electric counter, any ionized neon tube firing the related evennumbered tube CT2, 4, 6 or 8, which quenches the related odd-numbered tube. The digit code (Fig. 2, not shown) is such that either or both of tubes CT6, CT8 is ionized at the registration of a digit to send a pulse across condenser C14 or C15 to fire cold-cathode tube CT9 and operate relay ST, which de-energizes the transfer relay TR and operates relay S. Impulse sender. At the next opening of machine-operated contacts Zs, relay IG energizes and when these contacts close, relay I energizes. Contacts ig3 discharge a condenser C9 to reverse the condition of the first pair of tubes CT1, CT2. When the contacts Zs reclose, relay I energizes to recharge condenser C9. Contacts ig2 remove a short-circuit from contacts Zl too late for an impulse to be sent to line during the first opening of the contacts, but all subsequent openings send an impulse to line and also de-energize relay I to discharge C9 again. Each discharge of the condenser C9 subtracts unity from the electric counter, the arrangement being that ionization of an oddnumbered tube passes a pulse through transformer T1, 2 or 3 to the next higher pair of tubes. When all the odd-numbered tubes are ignited, the counter is restored to its original condition and a kick-over transformer T4 fires tube CT10 to operate terminating relay T, which quenches tube CT9 to release relays ST and S. Relay T also short-circuits the lines l1, l2 to prevent further impulses going out and releases relays I, IG. Release of relay S causes operation of relay B to connect up the second set of storage tubes. A time interval between successive trains of impulses is provided by charging of condenser C18 over contacts tl before firing tube CT11, which operates relay ID to discharge C18, quench tube CT10 and operate relay TR. The process repeats for the emission of a train of impulses for each stored digit. After sending the eighth digit, if so many are stored, the release of relay H operates a clear-down relay CL which restores the circuit to normal. If less than eight digits are stored, the absence of a digit to be transferred means that neither of tubes CT6, 8 ignites, tube CT9 does not fire and relay ST does not operate. Clear-down relay CL then energizes slowly. Cancellation. When an incorrect digit is keyed, operation of a cancel key CK energizes a cancel relay CA to extinguish all tubes of the storage circuit and to de-energize all of the chain of relays A-H. Modifications. The storage tubes may be dispensed with if an electric counter is provided for every digit. The transformers T1-4 may be replaced by condensers and rectifiers, or by neon tubes. By inserting a cross-connection frame between the storage sets and the counting sets, translated digits may be sent out. Reference is made to Specification 621,817.