| 摘要 |
<p>: The invention relates to a high speed central office scanner for use with a plurality of transponding units connected by telephone lines. The scanner is comprised of N, I/O units (30), each comprised of a multiplexer (70) for connecting the I/O units to M telephone lines; a microprocessor (48) and multiplex logic (66) which sequentially selects one of the M telephone lines; a busy detect circuit (68) for checking the selected telephone line and providing a signal when the line is busy; a TX/RX unit (54) connected to the selected line for transmitting an instruction code to a transponder connected thereto when the signal is absent and for receiving data from the transponder in response to the instruction code; and a storage unit (58). The scanner further includes a master microprocessing unit (26), which includes a main microprocessor (34) for sequentially selecting one of the N, I/O units and for generating an interrogating code for transmission to each selected I/O unit. Each master microprocessor unit includes a master storage unit (36) for storing received data from the selected I/O unit and a main TX/RX unit (32) for transmitting the received data stored in the main storage unit, upon receipt of a further interrogation code, wherein each of the N, I/O units scan the M telephone lines independently and asynchronously with respect to each other of the N, I/O units and the master microprocessing unit.</p> |
