Method and apparatus for enabling dual control head operation of a mobile radio transceiver

• US 20040147231A1
• Filed: 01/29/2003
• Published: 07/29/2004
• Est. Priority Date: 01/29/2003
• Status: Active Grant

• Current Assignee: Marler Communications, Inc.
• Original Assignee: Marler Communications, Inc.
• Inventors: Sublette, Alexander Thomas, Marler, Eric Scott
• Granted Patent: US 7,142,825 B2
• Time in Patent Office: Days
• US Class Current: 455/90.1
• CPC Class Codes: H04B 1/401 for selecting or indicating operating mode

Abstract

An apparatus and corresponding method for enabling the use of a plurality of control heads for operating a transceiver designed to operate with a single control head via a data bus. An interface module is connected between the transceiver and the plurality of control heads that periodically generate an interrupt request. The interface module, responsive to the interrupt requests, selectively enables one of the control heads to operate the radio transceiver. The method includes polling communication from the control heads and transceiver for mediating control of the transceiver. In one embodiment, accessibility of the radio system is improved and cost reduced by utilizing the speaker and volume control of each control head, such that an external speaker is not required.

Claims

1. In a radio system including a transceiver designed to operate with a single control head via a digital data bus, a method for enabling the use of a plurality of control heads for operating said transceiver, each said control head periodically generating an interrupt request signal, comprising the steps of:

connecting an interface module between said transceiver and said plurality of control heads;

detecting in said interface module when one said control head has generated an interrupt request; and

causing said interface module to selectively enable the control head that generated said interrupt request to operate said transceiver.

2. The method of claim 1, wherein the method is implemented using two control heads and the step of causing said interface module to selectively enable comprises the steps of:

processing said interrupt request;

designating said requesting control head as the active control head and the other control head as the inactive control head;

forwarding said interrupt request to said transceiver;

receiving a message from said transceiver;

forwarding said transceiver message to said control heads;

receiving data messages from said control heads in response to said transceiver message; and

selectively forwarding said received data messages from said active control head to said transceiver, thereby enabling operation of said transceiver by said active control head.

3. The method of claim 2, further comprising the step of:

setting a timeout period when an interrupt request is generated by each of said control heads at the same time, such that no interrupt requests are processed during said timeout period.

4. The method of claim 2, further comprising disabling the receiving of said interrupt requests while an interrupt request while an interrupt request is being processed.

5. The method of claim 2, further comprising the step of reenabling the receiving of said interrupt requests after said received data messages have been forwarded from said active control head to said transceiver.

6. The method of claim 2, wherein the step of forwarding said transceiver message to said control heads includes the steps of:

decoding said transceiver message to determine if said transceiver message is a backlighting control message; and

if said transceiver message is a backlighting control message, then

forwarding said backlighting control message to said active control head; and

forwarding a backlighting no change message to the other of said control heads, such that a backlighting change in said backlighting control message is received only by said active control head;

if said transceiver message is not a backlighting message, then forwarding said transceiver message to each of said control heads.

7. The method of claim 2, wherein the step of receiving data messages from said control heads in response to said transceiver message, includes the steps of:

decoding said received message to determine if said received message is a volume control message sent from said active control head;

if said received message is said volume control message, then

retrieving volume control position information from said volume control message; and

processing said position information in response thereto to control the audio level of the speaker for the identified control head.

8. The method of claim 7, wherein said volume control message is sent from said active control head in response to rotation of a volume control knob thereon.

9. The method of claim 2, wherein the step of receiving data messages from said control heads in response to said transceiver message, includes the steps of:

decoding said received message to determine if said received message is a hookswitch message sent from said active control head in response to a change in the hookswitch status;

changing the state of the muting of a first audio speaker integrated in said active control head if said received message is said hookswitch message such that the volume of said first audio speaker is muted when said hookswitch message is an off hook message and unmuted when said hookswitch message is an on hook message and the volume of a second audio speaker integrated in a handset connected to said active control head is not muted, thereby providing speaker privacy to the user of said handset.

10. An interface module for selectively enabling the use of a first and second control head for operating a mobile radio transceiver designed to operate with a single control head via a digital data bus, said interface module coupled between said mobile radio transceiver and said first and second control heads and receiving the signals therefrom;

said interface module comprising;

a communications microcontroller having three serial communication channels (SCC) including;

a first serial communication channel connected to said first control head for sending data messages between said interface module and said first control head;

a second serial communication channel connected to said second control head for sending data messages between said interface module and said second control head;

a third serial communication channel connected to said transceiver for sending data messages between said interface module and said transceiver;

said interface module selectively forwarding messages received on said third channel to said first and second channels; and

an interrupt controller connected to the interrupt request lines of said control heads for monitoring interrupt request signals on said interrupt request lines and selectively forwarding said interrupt request signals to said transceiver;

a memory module coupled to said communications microcontroller to provide storage;

an audio circuit module for providing control of the audio gain of said control heads in response to user actions on said control heads; and

a logic circuit for providing control to switch the power state of the interface module in response to changes in the power state of said transceiver.

11. The interface module of claim 10, further comprising:

code for polling each of said channels periodically for messages to be transmit or received;

code for processing the interrupt service request received on said first and second channels code for selectively forwarding said interrupt service requests to said transceiver via said third channel;

code for receiving messages from said transceiver responsive to said interrupt service requests;

code for selectively forwarding said transceiver messages to said first and second control heads; and

code for processing messages from said requesting control head, responsive to said transceiver messages.

12. The interface module of claim 11, wherein said code for processing said interrupt service request designates the source of said interrupt service request as the active control head.

13. The interface module of claim 12, wherein the interface module further comprises:

code for processing volume control messages sent by one of said control heads in response to rotation of a volume control knob thereon when said sending control head is said active head;

said code comprising;

code for retrieving volume control position information from said volume control message;

code for processing said position information in response thereto; and

code for sending an audio level corresponding to said position informatoin to said audio circuit module.

14. The interface module of claim 10, wherein said audio circuit comprises:

a dual channel digital-to-analog converter (DAC); and

a dual dc-gain-controlled amplifier stage providing control of the audio level of one or more audio speakers for each of said control heads, the output of said DAC being sent to said amplifier stage in response to changes in the position of the volume control knob for the active control head.

15. The interface module of claim 14, wherein said one or more audio speakers for each of said control heads comprises:

one or more audio speakers integrated in said control head; and

a handset audio speaker integrated in a handset connected to said control head.

16. The interface module of claim 15, further comprises:

code for processing a hookswitch command from said active control head; and

code for controlling said dual dc-gain-controlled amplifier stage in response to said hookswitch command such that the audio level for said one or more audio speakers integrated in said active control head alternates between a muted and unmuted state when said hookswitch command is received and the audio level for said handset audio speaker for said active control head is not muted;

thereby enabling a speaker privacy mode for the user operating said active control head.

17. The interface module of claim 14, wherein said one or more audio speakers for each of said control heads comprises:

one or more audio speakers integrated in said control head;

an external speaker connected to said control head; and

a handset audio speaker integrated in a handset connected to said control head.

18. The interface module of claim 17, further comprises:

code for processing a hookswitch command from said active control head; and

code for controlling said final audio amplifier stage in response to said hookswitch command such that the audio level for said one or more audio speakers integrated in said active control head and for said external speaker connected to said active control head is muted when said hookswitch command is an off hook command and is unmuted when said hookswitch command is an on hook command and the audio level for said handset audio speaker for said active control head is not muted, thereby enabling a speaker privacy mode for the user operating said handset of said active control head.

19. A mobile radio system comprising:

a radio transceiver designed to enable operation by only a single control head;

a plurality of control heads, each of said control heads periodically generating an interrupt request; and

an interface module connected between said radio transceiver and said control heads;

said interface module, responsive to said interrupt request;

selectively enabling one of said control heads to operate said radio transceiver.

20. In a radio system including a transceiver designed to operate with a single control head via a digital data bus, a method for enabling the use of a pair of control heads for operating said transceiver, comprising the steps of:

(a) providing an interface module connected between said transceiver and said pair of control heads, each of said control heads periodically generating an interrupt request;

(b) initializing said interface module;

(c) receiving one of said interrupt requests from one of said control heads;

(d) processing said interrupt request;

(e) designating said requesting control head as the active control head and the other control head as the inactive control head;

(f) forwarding said interrupt request to said transceiver;

(g) polling a first one of said pair of control heads to determine if said first control head has data ready to be transmit to said transceiver;

(h) if said first control head has data ready to be transmit, polling the interrupt requests from each of said control heads to ensure that only one of said control heads has an interrupt request currently active;

(i) sending said currently active interrupt request said transceiver;

(j) polling said transceiver to determine if said transceiver has data ready to be transmit to said control heads;

(k) if said transceiver has data ready to send to said control heads, checking said data to determine if said data contains a backlighting message;

(l) if said data from said transceiver does not contain said backlighting message, sending said data to each of said control heads;

(m) if said data from said transceiver contains said backlighting message;

processing said backlighting message, wherein said processing includes;

(m1) sending said backlighting message to said active control head,

(m2) sending a backlighting no-change message to said inactive control head; and

(m3) then returning to step (g);

(n) if said transceiver does not have data ready, determining whether said first control head is the active control head and has data ready;

(o) if said first control head is either not the active control head or does not have data ready, determining whether the other control head is the active control head and has data ready and if said other control head is either not the active control head or does not have data ready, then proceed to step (g);

(p) if it is determined that one of said pair of control heads is an active control head with data ready, processing the data of said active control head, said processing comprising;

(p1) determining if said data contains audio or hookswitch information;

(p2) if said data does not contain audio or hookswitch information, sending said data to said transceiver and returning to step (g);

(p3) if said data does contain audio or hookswitch information, processing said information such that any change in audio volume as a result of said information occurs only for speakers corresponding to said active control head.