High speed central office scanner

• US 4,287,567 A
• Filed: 07/31/1979
• Issued: 09/01/1981
• Est. Priority Date: 06/01/1978
• Status: Expired due to Term

• Current Assignee: AEL Microtel Limited 108-4664 Lougheed Highway Burnaby British Columbia
• Original Assignee: Universal Industrial Control Devices Limited
• Inventors: Lumsden, James R.
• Primary Examiner(s): Shaw, Gareth D.
• Assistant Examiner(s): Chan, Eddie P.
• Application Number:
  US06/062,529
• Time in Patent Office: 763 Days
• Field of Search: 364/200 MS File, 364/900 MS File, 179/18 ES, 179/18 AB, 179/18 FG, 179/2 DP, 179/2 R
• US Class Current: 370/449
• CPC Class Codes: H04M 11/002 with telemetering systems telemetering in general G08C
• CPC Class Codes: H04Q 3/00 Selecting arrangements H04Q5/00 - H04Q11/00 take precedence

Abstract

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, each comprised of a multiplexer for connecting the I/O units to M telephone lines; a microprocessor and multiplex logic which sequentially selects one of the M telephone lines; a busy detect circuit for checking the selected telephone line and providing a signal when the line is busy; a TX/RX unit 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. The scanner further includes a master microprocessing unit, which includes a main microprocessor 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 for storing received data from the selected I/O unit and a main TX/RX unit 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.

Claims

1. A high speed central office scanner for communicating with a plurality of transponding units connected by telephone lines;

said scanner is comprised of;

A. N, I/O means, where N is a positive integer, each I/O means comprising;

(a) multiplex means for connecting said I/O means to M telephone lines, each telephone line being connected to at least one transponder, where M is a positive integer;

(b) a microprocessor;

(c) multiplex logic means, controlled by said microprocessor for sequentially selecting one of said M telephone lines;

(d) a bush detect means for checking said selected line and producing a signal when said selected line is busy;

(e) transmitting-receiving means connected to said selected line, controlled by said microprocessor for transmitting an instruction code to a transponder connected thereto when said signal is absent, and receiving data from said transponder in response to said instruction code;

(f) storage means; and

(g) I/O interface logic means,

wherein said microprocessor analyzes the received data and enters the received data in said storage means if the received data satisfies a predetermined criterion;

B. master microprocessor means comprising;

(a) interface logic means connected with said I/O interface logic means of each of said N, I/O means;

(b) a main microprocessor for sequentially selecting one of said N, I/O means and for generating an interrogation code for transmission to each selected I/O means to enquire if said selected I/O means has received data stored therein;

(c) main storage means for storing received data from said selected I/O means; and

(d) main transmitting-receiving means for transmitting said received data stored in said main storage means upon receipt of a further interrogation code;

wherein each said N, I/O means scan said M telephone lines independently and asynchronously with respect to each other of said N, I/O means and said master microprocessor means.

2. The scanner according to claim 1, further including a central computer connected to P, said master microprocessing means so that the scanner now contains NP, I/O means scanning MNP telephone lines, where P is a positive integer;

said central computer sequentially selecting each of said P master microprocessor means, said central computer generating said further interrogation code and receiving the received data transmitted from said selected master microprocessing means.

3. The scanner according to claim 2 further comprising a data concentrator is connected between said central computer and said P master microprocessors, said data concentrator being connected to a direct memory access port of said central computer, said data concentrator comprising a direct memory access interface connecting said direct memory access port and a data concentrator master microprocessor, said data concentrator master microprocessor being connected to P data concentrator slave microprocessors each of which is connected in a one-to-one correspondence with said P master microprocessors, wherein said data concentrator master microprocessor sequentially selects each of said P data concentrator slave microprocessors and generates said further interrogation code and receives data transmitted from said selected master microprocessor means for transmitting to said central computer.

4. The scanner according to claim 2, wherein said P master microprocessor means are connected to said central computer via P high speed links, each of said P high speed links includes a first data set located adjacent said master microprocessing means for converting digital data stored in said main storage means for transmission to said central computer into signals for telephone line transmission and for converting telephone signals from said central computer into digital data for use by said master microprocessing means, and a second data set located adjacent said central computer for converting digital data produced by said central computer into signals for telephone line transmission for transmission to said first data set and for converting telephone signals transmitted by said first data set into digital data for use by said central computer.

5. The scanner according to claim 3, wherein said P master microprocessor means are connected to said central computer via P high speed links, each of said P high speed links includes a first data set located adjacent said master microprocessing means for converting digital data stored in said main storage means for transmission to said central computer into signals for telephone line transmission and for converting telephone signals from said central computer into digital data for use by said master microprocessing means, and a second data set located adjacent said data concentrator for converting digital data produced by said central computer into signals for telephone line transmission for transmission to said first data set and for converting telephone signals transmitted by said first data set into digital data for use by said central computer.

6. The scanner according to claim 1, wherein said multiplex means includes M double-pole, single-throw solid state switches, with each switch of said M switches being connected to one of said M telephone lines in a one-to-one correspondence so that each of said M telephone lines is selectively connected to said scanner.

7. The scanner according to claim 6, wherein each said switch is activated by a select signal produced by said microprocessor and wherein each said switch is operated by a power supply having one of its polarities connected to a logic ground;

wherein each of said M telephone lines is comprised of a tip line and a ring line;

wherein said tip line is terminated to a central office ground, via a portion of said busy detect means, and wherein said logic ground is isolated from said central office ground.

8. The scanner according to claim 7, wherein said busy detect means includes a light emitting diode connected between said tip line of said selected telephone line and said central office ground, said LED being forward biased only by a voltage appearing between said tip line and said central office ground when said selected telephone line is in use, and a phototransistor located directly adjacent said light emitting diode, said phototransistor being biased into a conductive state as a result of the forward biasing of said LED.

9. The scanner according to claim 6, wherein each said switch is activated by a select signal produced by said microprocessor and wherein each said switch is operated by a power supply having one of its polarities connected to a logic ground;

wherein each of said M telephone lines is comprised of a tip and a ring line wherein said tip and ring lines are isolated from said logic ground; and

wherein said busy detect means is connected across the tip and ring lines of said selected telephone line, said busy detect means comprising full wave bridge rectifier means connected to said selected tip and ring lines via a resistor means, a light emitting diode connected across said rectifying means;

a phototransistor connected as an analog amplifier the output of which is connected to a Schmitt trigger means, said analog amplifier being biased to produce a signal at the output of said Schmitt trigger means when the DC voltage across said selected tip and ring lines drops below a predetermined DC voltage thereby indicating a busy condition on said selected telephone line.