公开(公告)号：DE1179738B

公开(公告)日：1964-10-15

申请号：DEJ0023069

申请日：1963-01-29

Applicant: IBM

Inventor： BARKER HAROLD DESMOND ,  STAFFORD THOMAS SANDERSON

IPC: G06F3/00 ,  G06F7/02 ,  G06F13/38 ,  H04J3/16 ,  H04L5/22 ,  H04L13/08

Abstract: 963,959. Telegraphy. INTERNATIONAL BUSINESS MACHINES CORPORATION. Jan. 2, 1963 [Feb. 1, 1962], No. 245/63. Heading H4P. The invention provides a device which can receive low speed data simultaneously from a plurality of sources, pass the data at high speed to a central computer, receive data from the computer, and pass it to the respective data source; each data source has one of a plurality of predetermined transmission rates, data being handled in blocks of 100 characters. Each data source line is scanned during a fraction of the smallest bit, and the device establishes a data sampling rate for each line compatible with the transmission rate of the data received on that line. The apparatus accommodates up to 30 incoming lines but the system is described here with reference to the Figure which shows the data received on 5 lines. The data on a particular line has always one of three bit rates, designated Type A, Type B and Type C. The frequency of an oscillator is a multiple of each of the bit rates; in the example the repetition frequencies of Types A : B : C are 5: 7 : 14. The output 201 of the oscillator feeds counters A, B, C, which respectively count to 5, 7 and 14. Counter C is arranged so that only odd counts are effective, the representation of counter C output therefore being as shown. All 30 lines are scanned sequentially during period 202. Each incoming line is connected to an A, B, or C terminal by way of a plugboard, dependent upon the data bit rate. Upon receipt of the start of a data block the count of the relevant counter is added to part of a control word, derived from a store. Consider Line 1 (Type B bit rate). The start 208 arrives as counter B indicates 2. To this count is added a predetermined number, 3. For Type A data this number is 2 and for Type B is 3. The total, 5, is stored in the control word, and each time counter B reaches this total, which is at the approximate mid-point of each bit, line 1 is sampled and the sample passed to a data store. The control words are changed synchronously with the line scan and each word indicates the time at which the line is to be sampled (as above described), the address in the data store to which the received character is to be fed prior to read-out of a complete block at high speed to the computer, the message block, and parity and other information. The data store also contains data received from the computer for transfer to the lines.