Priority line switching system

• US 5,787,155 A
• Filed: 11/04/1994
• Issued: 07/28/1998
• Est. Priority Date: 11/04/1994
• Status: Expired due to Term

• Current Assignee: Physio-Control Incorporated (Stryker Corporation)
• Original Assignee: Physio-Control Incorporated (Stryker Corporation)
• Inventors: Luna, Michael E. S.
• Primary Examiner(s): WOO, STELLA L
• Application Number:
  US08/334,787
• Time in Patent Office: 1,362 Days
• Field of Search: 379/106, 379/107, 379/102, 379/104, 379/105, 379/94, 379/93, 379/98, 379/97, 379/96, 379/38, 379/93.09, 379/93.11, 379/100.15, 379/100.16, 379/106.01 , 379/106.02, 379/102.01, 379/102.02, 379/102.07, 379/93.26, 379/93.28, 379/93.23, 379/93.01
• US Class Current: 379/93.09
• CPC Class Codes: G06F 13/4022 using switching circuits, e.g. switching matrix, connection or expansion network G06F13/4009 takes precedence
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors

Abstract

The serial data port of a terminal device is normally connected to a peripheral device for data transfer. A telephone connection with a public switched telephone network (PSTN) is monitored to detect, however, if there is an incoming priority data message. If so, the terminal device is notified of the priority message and is allowed to terminate its current data transfer with the peripheral device. The terminal device is then connected to the PSTN to receive the priority message. At the conclusion of the priority message, the terminal device is reconnected to the peripheral device to complete the interrupted data transfer. In this way, the serial port of the terminal device can be used for data transfer with different peripherals, without jeopardizing or delaying reception of a priority data message.

Claims

1. A priority line switching apparatus for connection between a first device for transmitting and receiving data messages, and two or more peripheral devices, including a first peripheral device for comnmunicating data messages with the first device and a second peripheral device for communicating data messages with the first device, the second peripheral device supplying an indicator signal when a data message is to be transmitted to the first device, the apparatus comprising:

a switch having a first connection for coupling to the first device, a second connection for coupling to the first peripheral device, and a third connection for coupling to the second peripheral device, said switch being operable in a first mode of operation to connect the first connection with the second connection and in a second mode of operation to connect the first connection with the third connection, for conveying data messages therebetween; and

control means normally maintaining the switch in the first mode of operation to allow transmission of a data message between the first device and the first peripheral device, said control means including means for monitoring the third connection for receipt of an indicator signal from the second peripheral device during transmission of the data message, and for automatically supplying a first control signal to the switch to interrupt the transmission of the data message with the first peripheral device and change from the first mode of operation to the second mode of operation upon receipt of the indicator signal.

2. The apparatus of claim 1, wherein the control means includes means for detecting the indicator signal and for supplying the first control signal to the switch upon such detection.

3. The apparatus of claim 2, wherein the control means includes means for generating a break signal and transmitting the break signal to the first device to indicate to the first device that a data message is to be received from the second peripheral device.

4. The apparatus of claim 3, wherein the control means includes means for generating a second control signal to the switch within a predetermined period after supplying the first control signal to change the switch back to the first mode of operation and allow the first device to terminate transmission of data messages with the first peripheral device.

5. The apparatus of claim 4, wherein the control means includes means for generating a third control signal to the switch within a predetermined period after supplying the second control signal to change the switch to the second mode of operation and allow the first device to receive the data message from the second peripheral device.

6. The apparatus of claim 5, wherein the control means includes means for generating a fourth control signal to change the switch to the first mode of operation after the data message has been received from the second peripheral device.

7. The apparatus of claim 1, wherein the second peripheral device is a portable physiological instrument.

8. A priority line switching apparatus for selectively connecting a first device to a peripheral device and a public switched telephone network to allow the first device to transmit data messages to the peripheral device and receive data messages from a remote device over the public switched telephone network, the public switched telephone network supplying an indicator signal when a data message is to be received, the apparatus comprising:

a switch having a first connection for coupling to the first device, a second connection for coupling to the peripheral device, and a third connection for coupling to the public switched telephone network, the switch being operable in a first mode of operation to connect the first connection with the second connection and in a second mode of operation to connect the first connect and the third connection, for conveying data messages therebetween; and

control means normally maintaining the switch in the first mode of operation to allow transmission of data messages from the device to the peripheral device, said control means including means for monitoring the third connection for receipt of an indicator signal from the public switched telephone network during transmission of data messages between the first device and the peripheral device and for automatically supplying a first control signal to the switch to interrupt the transmission of data messages and change from the first mode of operation to the second mode of operation upon receipt of the indicator signal.

9. The apparatus of claim 8, further comprising a modem coupled between the third connection and the control means for modulating and demodulating data messages conveyed between the first device and the public switched telephone network.

10. The apparatus of claim 9, further comprising an interface circuit coupled between the modem and the third connection for generating a ring indicator (RI) signal indicative of a data message transmitted over the public switched telephone network and for providing the RI signal to the modem and the control means.

11. The apparatus of claim 10, wherein the control means includes means for detecting the RI signal and for supplying the first control signal to the switch upon such detection.

12. The apparatus of claim 11, wherein the control means includes means for generating a break signal and transmitting the break signal to the first device to indicate to the first device that a data message is to be received from the public switched telephone network.

13. The apparatus of claim 12, wherein the control means includes means for generating a second control signal to the switch within a predetermined period after supplying the first control signal to change the switch back to the first mode of operation to allow the first device to terminate transmission of data messages with the peripheral device.

14. The apparatus of claim 13, wherein the control means includes means for generating a third control signal to the switch within a predetermined period after supplying the second control signal to change the switch to the second mode of operation to allow the first device to receive the data message from the public switched telephone network.

15. The apparatus of claim 14, wherein the control means includes means for generating a fourth control signal to change the switch to the first mode of operation after a data message has been received from the public switched telephone network.

16. The apparatus of claim 15, wherein the control means supplies the first control signal at the onset of a ring indicator (RI) signal, the second control signal during such RI signal and the third control signal at the conclusion of such RI signal.

17. The apparatus of claim 8, wherein the data messages are transmitted serially.

18. The apparatus of claim 8, wherein the data messages are transmitted in parallel.

19. The apparatus of claim 8, wherein the switch includes a multiplexer.

20. The apparatus of claim 8, wherein the remote device is a portable physiological instrument.

21. A method of selectively switching a connection between a data port on a terminal device, a first port coupled to a peripheral device, and a second port coupled to a remote device by a telephone line to allow reception of a priority data message over the telephone line by the terminal device, the priority data message preceded by a ring signal, the method comprising the steps of:

(a) connecting the data port on the terminal device to the first port on the peripheral device to allow data transmission between the terminal device and the peripheral device;

(b) monitoring the second port that is coupled to the remote device by a telephone line to detect a ring signal during data transmission between the terminal device and the peripheral device;

(c) breaking the connection between the data port and the first port upon detection of the ring signal;

(d) transmitting a break signal to the terminal device to signal the terminal device to terminate data transmission with the peripheral device;

(e) reconnecting the data port and the first port to allow the terminal device to terminate the data transmission with the peripheral device;

(f) breaking the connection between the data port and the first port after the terminal device has terminated the data transmission with the peripheral device; and

(g) connecting the data port with the second port to allow the terminal device to receive a priority data message over the telephone line.

22. The method of claim 21, further comprising the steps of:

(a) breaking the connection between the data port and the second port after the priority data message is received; and

(b) reconnecting the data port with the first port to allow the terminal device to complete the data transmission with the peripheral device.

23. The method of claim 21, wherein step (c) is performed on a rising edge of the ring signal.

24. The method of claim 23, wherein step (f) is performed on a falling edge of the ring signal.