| 摘要 |
1,134,413. Telegraphy. AUTOMATIC TELEPHONE & ELECTRIC CO. Ltd. 3 Nov., 1966 [4 Nov., 1965], No. 46856/65. Heading H4P. A buffer connected between a telegraph exchange and a two-way simplex subscriber line comprises a shift register and a store so arranged that on reception of a character signal the bits are fed in serially to the register and from thence passed in parallel, and without Start and Stop bits, via the store to the exchange. In the reverse direction the exchange passes a parallel signal via the store to the register, where it is serialized. Start and Stop bits are added and the signal is transmitted to the subscriber. In the embodiment, the operation of which is described in detail, the clock controlling the register during reception is started by the received Start bit. A parity bit is added to the register output. When the store contains the character information bits and the parity bit it informs the exchange, which subsequently addresses the store and reads it. When the exchange wishes to transmit it starts the clock and if the line is free sends a character signal with a parity bit to the register. The parity of signal bits transmitted is compared with that parity bit to detect any error. |
