Patent GB-1000170-A (GB)
Title: Code converter
IPC: H03M7/00
Filed: 1963-01-01
Abstract: 1,000,170. Electric selective signalling. COMMERCIAL CONTROLS CORPORATION. Jan. 1, 1963 [Feb. 12, 1962], No. 111/63. Heading G4H.  A code converter performs a binary-to-decimal (binary to 1-out-of-n) conversion on each of two code-bit sub-groups within a received permutational code-bit group, the decimal evaluations being converted to an energization of an individual one of a plurality of electrical circuits either to generate a code group in a new permutational code or to continue operations by recognizing that the energized electrical circuit corresponds to no group in the new code.  Any 5- or 6-channel code and various 7- and 8-channel codes are usable for the input and output of this converter. Eight sensing pins in an input punched-tape reader control a network of switches to energize one of a set of relays depending on the bits in columns 1-3 of the input code group and one of another set of relays depending on bits 4-6. By changing terminal connections, relays which respond to the 6th bit may be made to respond to the 7th bit instead. Another relay is energized if a " ONE " occurs in the 7th or 8th (depending on terminal connections to be made) bit column: this relay controls so-called " 8th bit selectors " to be described. Contacts controlled by the. 1-6 bits relays set up energization circuits to one set of four plug-hubs (in rows A-H) on a plug-board (one quarter of which is shown in Fig. 1a, the rest in Figs. 1b-1d, not shown): those bit columns in which " ONES " occurred are specified by the digits written on each hub in Fig. 1. " 123 bit selectors " and " 456 bit selectors " also to be described, are also controlled by the above relays. The fourth (from the left in Fig. 1) of the four plug-hubs mentioned above is energized slightly before the other three. For example, reading of a code group having " ONES " in places one and six (only) results in energization of hub D8 followed by hubs D5-D7. To achieve the punching of an output tape in a different code, these A-H hubs must be wired to hubs in rows I-P on the board. The I-P hubs in columns 5-32 consist of seven repetitions of the I-P hubs in columns 1-4 (apart from hub P3 which is not repeated), for convenience of wiring, corresponding hubs in the eight sets being electrically interconnected. I-P hubs with numbers written on them in Fig. 1, when energized, actuate the output punches whose numbers are written on the hubs. The other I-P hubs provide functional control of the converter and those energized from A-H hubs are to be energized from the fourth hubs of the sets of four hubs mentioned. The functional control hubs in rows I-P (columns 1-4) are: " Non-punch " I4: used when the reading of an input code group is not to result in the punching of an output group. " Stop " K4: stops the converter. " Letters and figures precedence," N4 and 04: used with a 5-channel output tape and, when energized, energize a letters or a figures memory relay (if this is not already energized) respectively. Only one of the two relays can remain energized at a time. When either relay is newly energized, the letters or figures shift code group (12345 or 1245) is inserted in the output tape, without benefit of wiring to I-P numbered hubs. " No precedence " P4. " Shift to letters and figures " L4 and M4: used with a 5-channel input or output tape and can control the letters and figures memory relays. With a 5-channel output tape, these hubs are used for inserting extra shift to letters and figures code groups in the output tape (e.g. for buffering purposes). With a 5-channel input tape they are used to insert a " ONE " in channel 6 of the output tape if the input code group is of the figures shift type. "Automatic line feed " J4: used with a 5- channel standard telecommunications output code to achieve punching of a carriage return output code group followed by n line feed output groups, in response to reception of n successive carriage return input groups. " Gap entry" O3: halts reading of input tape and continues production of output tape (blank) for a time dependent on the timeconstant of an R.C. circuit with adjustable resistor. " Gap exit P3: automatically energized during the gap initiated by energization of hub O3. Other hubs: An " all codes " hub Q8 is automatically energized whenever an input code group is read. An " input " hub R7 must be wired to a hub Q6 or to a hub Q7 depending on whether the input code is 5-channel or 6-, 7- or 8-channel respectively. " Tape feed exit " hubs Q9-Q12 are automatically energized during the " tape-feed " operation and are used for achieving the punching in the output code of a " tape feed "  code group, by means of wiring to I-P numbered hubs.  A " parity exit hub " R4, for use with a 5- channel output tape, is automatically energized every time the figures shift code group 1245 is punched in the output tape, and if wired to hub J3, achieves the concurrent actuation of the channel 7 output punch. This does not result in a hole in the output tape but prevents the giving of an alarm on punching of code group 1245 when odd-parity checking is being used. The letters shift code group 12345 already has an odd number of " ONES." " 8th bit selectors " hubs T-V, 1-8 are provided and whenever a " ONE " is read in the input tape in column 7 or 8 (depending on terminal connections mentioned) hubs VI-V8 are connected to hubs T1-T8 respectively: otherwise V1-V8 are connected to hubs U1- U8, respectively. Hubs U1-U8 and T1-T8 are connected, in general, to different I-P- hubs, and hubs VI-V8 are connected to A-H hubs. Eight pairs of " 123 bit selectors " hubs are provided in rows W and X, one pair of hubs being electrically interconnected when each possible permutation of input bits in columns 1-3 is read. The " 123 bit selectors," along with " 456 bit selectors " in rows Y and Z which operate similarly, are used in conjunction with " power source " hubs S2-S5 (energized whenever an input code group is read) for energizing " tape skip " and " tape restore " hubs X9, Y9. When hub X9 is energized, reading of input code groups continues without output punching until hub Y9 is energized. Thus connecting each of X9 and Y9 to one of hubs S2-S5 by way of the appropriate pairs of YZ and WX hubs, " tape skip " and " tape restore " are achieved on the reading of any desired input groups. The only hubs on the plug-board not mentioned so far belong to three " special selectors." " Special selector No. 1 " has a " pick entry " hub Q13 which, when energized, energizes a relay achieving the connection of a " pick exit " hub Q14 to hub Q13, and hubs T14-T16 to hubs R14-B16 respectively. When a " drop entry " hub Q15 is energized the relay is deenergized, the aforesaid connections are broken, hub Q15 is connected to a " drop exit " hub Q16, and hubs T14-T16 are connected to hubs S14-S16 respectively. " Special selectors Nos. 2 and 3 " have similar hubs and may be operated independently or alternatively the relay of either may be controlled by hubs Q13 and Q15 of Selector No. 1. If Selector No. 2 or 3 is operated independently of Selector No. 1, two extra trios of hubs (similar to those corresponding to hubs R-T, 14-16 of Selector No. 1) are then usable in each selector, but the pick and drop entry hubs are not used. These special selectors can be used to alter the output code in response to particular input code groups. In a number of cases, an output code group equivalent to the input code group which energized a hub (other than a numbered hub in rows A-P) can be punched, some hubs being provided especially to enable this to be done by wiring to numbered I-P hubs. To facilitate setting up the converter in cases where the input and output codes number the digit columns in a different order, the energization circuits to the relays mentioned in paragraph 2 above and to the punches each contain plug-hole pairs so that by suitable wiring between these, any relay or punch may be energized from any of the energization circuits. By appropriate wiring on the plug-board, a 7th channel parity bit can be added to output code groups. A parity check circuit comprises switches controlled by the output punches and actuates an alarm and stops the converter if an odd or an even number (as desired) of output punches are not actuated. Continued operation of the converter depends on the presence of input and output tapes in the machine and will also cease if the tape is too tight. A-H hubs corresponding to every assigned code group must be wired to I-P numbered hubs or to a " non-punch " hub, e.g. I4, or converter operation will cease after the reading of an input group not so connected. Some of the hubs mentioned above (e.g. " gap exit " P3) are provided to enable this to be done. This feature enables the converter to be stopped if a non-assigned group is read from the input tape. Specifications 831,111 and 832,908 are referred to.