System for providing secure telecommunication access to a computer

• US 4,922,521 A
• Filed: 03/08/1989
• Issued: 05/01/1990
• Est. Priority Date: 09/05/1986
• Status: Expired due to Fees

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Teule, Hendrik, Krikke, Germen K.
• Primary Examiner(s): BROWN, THOMAS
• Application Number:
  US07/320,728
• Time in Patent Office: 419 Days
• Field of Search: 379/95, 379/94, 379/196, 379/197, 379/198, 379/188, 379/211, 379/93, 379/189
• US Class Current: 379/93.02
• CPC Class Codes: G06F 21/313 using a call-back technique via a telephone network
• CPC Class Codes: H04L 63/101 Access control lists [ACL]

Abstract

A telecommunication exchange which provides secure access by only authorized terminals to a computer connected to the exchange. The control processor in the central control unit of the exchange is programmed to provide a "call-back" procedure in respone to a request from a terminal for access to the computer. The calling terminal enters by tone or pulse dialing, the address (such as a telephone number) of the computer together with an identification code. The control processor compares such identification code with a list stored therein of authorized identification codes and authorized terminals addresses corresponding thereto. If the identification code is authorized, the control processor causes a confirm signal to be transmitted from the exchange to the requesting terminal signifying to the user of such terminal to release its line, after which a ringing signal is transmitted to the authorized terminal address corresponding to the authorized code. When such authorized terminal then engages its line, the control processor causes the switching network to establish connection of such terminal to the computer. Since the security procedure is provided by the control processor, there is no need for an external security unit and secure access to the computer can be maintained even if call-forwarding facilities are provided by the exchange.

Claims

1. A telecommunication exchange for controlling the interconnection of an external computer connected thereto to any of a plurality of terminals also connected thereto over telephone lines, interconnection of the computer with a terminal requesting access thereto only being established if such terminals transmits an authorized identification code and has an address in accordance with a predetermined list of authorized identification codes and authorized terminal addresses corresponding thereto;

such exchange comprising;

a control processor which includes a receive memory for storing the identification code transmitted by a requesting terminal and an authorization memory for storing said list of authorized identification codes and authorized terminal addresses corresponding thereto;

said control processor being programmed to compare whether the identification code received from a requesting terminal and stored in the receive memory matches an authorized identification code stored in the authorization memory, and if there is such a match to identify the authorized terminal address corresponding to such authorized identification code;

a switching network controlled by said control processor to selectively interconnect any of the terminals connected to said exchange with said computer and to selectively transmit confirm signals and ringing signals to any of such terminals, a confirm signal signifying to a user of a terminal to release its line and a ringing signal signifying to a user of a terminal to engage its line;

said control processor being further programmed to carry out a security procedure such that upon determining that a requesting terminal has an authorized identification code said control processor causes said switching network to

(i) transmit a conform signal to the requesting terminal,

(ii) after the calling terminal line has been released, transmit a ringing signal to the authorized terminal address corresponding to said authorized identification code, and

(iii) after the terminal at the authorized address has engaged its line, interconnect such terminal with said computer.

2. A telecommunication exchange as claimed in claim 1 wherein said control processor includes a program memory for storing a program which controls the operation thereof in accordance with said security procedure, and said authorization memory is included in said program memory.

3. A telecommunication exchange as claimed in claim 1, characterized in that the identification code of a terminal forms part of the address to be dialed by a user of such terminal when requesting access to said computer.

4. A telecommunication exchange as claimed in claim 1, wherein the exchange is adapted to reroute calls directed to an original destination terminal to a designed divert-terminal, and further characterized in that said control processor controls said switching network to provide interconnection of said computer with an original destination terminal in accordance with said security procedure irrespective of the applied rerouting of calls directed to such terminal other than calls for providing interconnection of such terminal with said computer.

5. A process for use in a telephone exchange for controlling the interconnection of an external computer connection thereto to any of a plurality of terminals also connected thereto over telephone lines, interconnection of the computer with a terminal requesting access thereto only being established if such terminal transmits an authorized identification code and has an authorized address in accordance with a predetermined list of authorized identification codes and authorized terminal addresses corresponding thereto;

such process comprising;

receiving and storing in a receive memory in said exchange the identification code transmitted by a requesting terminal;

storing in an authorization memory in said exchange said list of authorized identification codes and authorized terminal addresses corresponding thereto;

comparing whether an identification code received from a requesting terminal and stored in the receive memory matches an authorization code stored in the authorization memory, and if there is such a match identifying the authorized terminal address corresponding to such authorized identification code; and

controlling a switching network in said exchange to

(i) transmit a confirm signal to the requesting terminal to signify to a user thereof to release its line,

(ii) after the calling terminal line is released, transmit a ringing signal to the authorized terminal address corresponding to said authorized identification code to signify to a user of such authorization terminal to engage its line, and

(iii) after said authorized terminal has engaged its line, interconnect such terminal with said computer.