COMMUNICATION SYSTEM HAVING
RECONFIGURABLE DATA TERMINALS
This application is a continuation of application Ser. 5 No. 565,744, filed Dec. 27, 1983, now abandoned.
This invention relates to a communication system for controlling communications between a variety of con- 10 nected data communication devices and, more particularly, to a method and apparatus for establishing compatible communications between a reconfigurable data terminal and other data devices having different operating parameters. 15
BACKGROUND OF THE INVENTION
Existing data terminals can operate in any of several operating modes which are established by the user setting parameters, such as duplex/simplex, synchronous- 20 /asynchronous, parity, etc. The terminal operating mode must be set by the user to enable compatible communicatin with a computer system. In many communication systems, these data terminals are time-shared among several types of computer systems each having 25 different operating parameters. In such a communication system, the user must check the terminal configuration and reconfigure the terminal if necessary to enable communication with a different computer system type.
To overcome this burdensome and technically com- 30 plicated process of manual reconfigration by the user, one prior art system described by Finch et al in U.S. Pat. No. 3,676,858, issued on July 11, 1972, uses automatically reconfigurable computer ports. In Finch et al the coding and transmission rate of the computer port is 35 set after an electrical connection is established with a remote terminal and after receiving and analyzing a single standard character sent at the transmission rate at which the terminal is configured.
One problem with the Finch et al arrangement is that 40 since most of the operating modes available in todays terminals, such as parity setting, number of stop bits, character/block transfer, etc., are not detectable by analyzing the signal characteristics of the standard character received at the computer port, the Finch et al 45 technique would not work. Consequently, the computer port must be manually reconfigured to enable compatible communications with many of the newer terminals. An additional limitation of the Finch et al arrangement is that the coding and transmission rate of 50 the computer port cannot be set until after a connection is established and the terminal sends the standard character.
Thus, there is a continuing need in the art to provide a method and apparatus for automatic reconfiguration 55 of a communication system to enable compatible communications between terminals and various types of computer equipment connected to the system.
SUMMARY OF THE INVENTION ^
The present invention provides a method and apparatus for enabling compatible communications between a terminal having reconfigurable operating parameters and various types of communication devices (e.g., computers). According to the present invention the terminal 65 sends one of a number of terminal reconfiguration signals to a communication system controller each identifying a specific reconfiguration request and in response
thereto the controller selects and transmits a predetermined reconfiguration command defining one or more operating parameters to be reconfigured at the terminal. The terminal receives the command and reconfigures itself according to the operating parameters contained therein.
According to one embodiment of the present invention in a communication system including a terminal, a controller and a plurality of communication devices switchably connectable to the terminal, the calling terminal sends a dialing reconfiguration signal to the controller specifying the device or group of devices to which compatible communications is requested. In response thereto the controller selects and sends a reconfiguration command to the terminal specifying one or more operating parameters to reconfigure the terminal to enable compatible communication with the specified device or group of devices.
BRIEF DESCRIPTION OF THE DRAWING
The detailed description of the invention will be more fully appreciated from the illustrative embodiment shown in the drawing, in which:
FIG. 1 is a block diagram of a communication system including a terminal, switch, processor, controller, and connected computer systems;
FIG. 2 illustrates the data frame format and the S bit frame format utilized, respectively, for the data and S channel data transmissions between the terminal and computer systems;
FIG. 3 shows an illustrative format of some of the S channel message set;
FIG. 4 shows a block diagram of a terminal in accordance with the present invention;
FIG. 5 illustrates the dialog of communications between the origination terminal, switch processor and destination computer;
FIG. 6 shows a flow chart of the operations of the switch processor;
FIG. 7 shows a flow chart of the operations of the terminal; and
FIG. 8 illustratively shows a table listing some of the reconfigurable terminal parameters which can be established from commands from switch processor.
FIG. 1 illustrates a general block diagram of the disclosed communication system including terminal 10, communications switch 11, controller (switch processor) 12, and connected communication devices (computer systems) 13A through 13N. Terminal 10 connects through switch 11 to one of several available computers 13A-13N under control of a switch processor 12. Computers 13A-13N may be part of or co-located with switch 11 or remotely located (reached through trunk or central office lines 14A-14N). Communications between terminal 10 and any of the computers 13A-13N may require terminal 10 to be reconfigured to match the communications parameters of the called computer.
It should be understood that the disclosed remote terminal configuration method and apparatus is not limited to terminal - computer communications. Using this invention, terminals may be configured to connect with other terminals, intelligent workstations, personal computers, information service bureaus, data switches, modems and line adapter units, etc. Moreover, while the disclosed embodiment uses a dialing signal from the calling terminal as a reconfiguration signal it should be