Control device for local connection of a peripheral unit through a modem interface for remote connection

• US 4,007,449 A
• Filed: 10/11/1974
• Issued: 02/08/1977
• Est. Priority Date: 11/09/1973
• Status: Expired due to Term

• Current Assignee: Honeywell Information Systems, Inc. (Honeywell International Inc.)
• Original Assignee: Honeywell Information Systems, Inc. (Honeywell International Inc.)
• Inventors: Vercesi, Giacomo
• Primary Examiner(s): Chapnick, Melvin B.
• Application Number:
  US05/514,144
• Time in Patent Office: 851 Days
• Field of Search: 340/172.5
• US Class Current: 710/58
• CPC Class Codes: G06F 13/4221 being an input/output bus, e.g. ISA bus, EISA bus, PCI bus, SCSI bus
• CPC Class Codes: H04L 5/143 for modulated signals H04L5/1469 takes precedence

Abstract

A control system for a variable speed peripheral device which is suitable for remote as well as for local connection of the peripheral device to a central processor. For remote connection, the central processor is coupled to the peripheral device by way of a transmission controller, a remote communication line, and the control system connected to the peripheral device. First and second modems terminate the communication line and are connected through standard interfaces to the transmission controller and to the control system respectively. For this connection, the character transmission rate must be lower than, or equal to, the minimum operating speed of the peripheral device. For local connection, the central processor is coupled to the peripheral device by way of the transmission controller, the control system and the standard interface connected thereto. The latter interface further includes a special output lead connected to indicate the status of the peripheral device to the transmission controller in response to signals received from a control circuit internal to the control system. The transmission controller is thus enabled to transfer data to the peripheral device in the local connection at a rate that varies to meet the instantaneous requirements of the peripheral device. The average transmission rate thus exceeds the transmission rate for remote connection which must conform to the minimum operating speed of the peripheral device.

Claims

1. An electronic control system for locally connecting a peripheral device to a control unit adapted to control the transmission of information signals to a remote terminal, said control system comprising:

means connecting said control system to said peripheral device, a standard modem interface including a plurality of leads coupling said control system to said control unit and adapted for remote signal transmission, said interface further including a special lead;

and circuit means coupled to said special lead and to said peripheral device, said circuit means being responsive to signals representative of the operating conditions of said peripheral device to provide one of two distinct electrical signal levels on said special lead for signaling to said control unit the state of readiness of said peripheral device to receive said information signals.

2. An electronic control system for locally connecting a peripheral device for reception of binary coded signals from a transmission control unit, said system comprising:

a standard modem interface including a plurality of leads coupled to said peripheral device for reception of said binary coded signals;

said interface further including a special interface lead;

means for providing control signals, said means including

a shift register coupled to one of said plurality of leads for serially registering indications of said binary coded signals applied thereto;

timing means coupled to said shift register for synchronizing the reception of said coded signals with respect to their transmission speed determined by said transmission control unit;

and circuit means responsive to said timing means and to said control signals, said circuit means being coupled to said peripheral device and to said special lead for applying one or the other of two electrical signal levels to said special lead in response to signals representative of the operating conditions of said peripheral device, said transmission control unit being coupled to said special lead and being responsive to one of said electrical levels to interrupt the transmission of said binary coded signals on said one of said plurality of leads.

3. An electronic control system for both remote connection of a peripheral device to a data processing system by a transmission line coupled to a modem at each end, as well as for local connection of said peripheral device to said data processing system in the absence of said modems, comprising:

a standard modem interface including a plurality of leads coupled to said peripheral device for connection to one of said modems and adapted for the reception of first signals from said data processing system;

said interface further including an additional interface lead;

and circuit means coupled to said peripheral device and to said additional lead, said circuit means being responsive to second signals representative of the operating conditions of said peripheral device for applying one of two electrical signal levels to said additional lead indicative of the capability of said peripheral device to accept said first signals.

4. The electronic control system of claim 3 and further including;

serial storage means coupled to a first one of said plurality of leads of said standard for receiving said first signals;

timing means coupled to said serial storage means for timing the serial registration of said first signals by said storage means as binary coded characters at the rate of transmission of said data processing system;

and decoder means coupled to said storage means for generating control signals in response to the storage of characters indicative of operations required to be performed by said peripheral device;

said circuit means including logic control means coupled to said decoder means and to said peripheral device responsive to said control signals and to said second signals for applying one of said two electrical signal levels to said additional interface lead.

5. A control system for connecting a peripheral device to a transmission control unit adapted to control the transfer of information signals from a connected data processing system, said transmission control unit being provided with a first standard modem interface including a plurality of leads, said first interface further including a special lead adapted to receive a bilevel signal either in remote connection through a pair of modem units and an intermediately connected communication line, or directly in local connection, said bilevel signal being representative of the cabability of said peripheral device to accept said information signals;

a second standard modem interface for coupling said peripheral device through a corresponding plurality of leads to one of said pair of modem units or to said transmission control unit, said second interface including an additional interface lead for connection to said special lead in said local connection, and circuit means coupled to said additional lead and to said peripheral device and responsive to signals representative of the operating conditions of said peripheral device for applying one of two distinct levels of said bilevel signal to said additional lead.

6. A control system as recited in claim 5 and further including serial storage means coupled to a first one of said plurality of leads of said second interface for receiving said information signals, timing means coupled to said serial storage means for timing said storage means to serially register said information signals as binary coded characters at the rate of transmission of said data processing system, and decoder means coupled to said storage means for generating control signals in response to the storage of characters indicative of operations required to be performed by said peripheral device, said circuit means including logic control means coupled to said decoder means and to said peripheral device and controlled by said timing means, said logic control means being responsive to said control signals and to said signals representative of the conditions of said peripheral device.