Hardware interface and protocol for a mobile radio transceiver

• US 4,903,262 A
• Filed: 08/14/1987
• Issued: 02/20/1990
• Est. Priority Date: 08/14/1987
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: General Electric Company
• Inventors: Dissosway, Marc A., Childress, Jeffrey S.
• Primary Examiner(s): Safourek, Benedict V.
• Assistant Examiner(s): Chin, Wellington
• Application Number:
  US07/085,490
• Time in Patent Office: 921 Days
• Field of Search: 340/825.08, 340/825.52, 340/825.54, 340/644, 340/724, 340/500, 370/90, 370/96, 370/85
• US Class Current: 370/327
• CPC Class Codes: H04L 1/0078 Avoidance of errors by organising the transmitted data in a format specifically designed to deal with errors, e.g. location forward error control, e.g. FEC, CRC H04L1/004; adaptive formatting H04L1/0006; mappings H04L27/00
• CPC Class Codes: H04L 1/1685 the supervisory signal being transmitted in response to a specific request, e.g. to a polling signal
• CPC Class Codes: H04L 2001/0092 Error control systems characterised by the topology of the transmission link
• CPC Class Codes: H04W 4/10 Push-to-Talk [PTT] or Push-On-Call services
• CPC Class Codes: H04W 76/45 for Push-to-Talk [PTT] or Push-to-Talk over cellular [PoC] services
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

A system and method for communicating control signals between a digital mobile transceiver, a digital control head, and a mobile data terminal over a common serial peripheral bus uses a message protocol and architecture which is efficient and yet provides great versatility and functionality without adding undue complexity. As mobile data terminals are becoming increasing important in digital trunked repeater systems, the efficiency provided by the signalling protocol disclosed herein (which is optimized for mobile data terminal messages) is a very important advantage.

Claims

1. In a digital mobile radio transceiver including radio frequency circuit means for transmitting and receiving radio frequency signals, and a digital signal processor connected to control said radio frequency circuit means, a method of communicating signals between a peripheral device and said digital signal processor over a serial data bus having first and second data lines and a service request line, said method comprising the steps of:

(1) seizing control of said service request line with said peripheral device;

(2) receiving, with said peripheral device, a poll message passed over said first data line in response to seizure of said service request line;

(3) applying, with said peripheral device, a preset identification code to said second data line in response to receipt of said poll message;

(4) receiving, with said peripheral device a further poll message passed over said first data line in response to application of said identification code to said second line, said further poll message including said preset identification code;

(5) applying, with said peripheral device, a data and/or command message to said second data line in response to receipt of said further poll message; and

(6) releasing said service request line.

2. A method as in claim 1 wherein said applying step (5) includes applying the following in sequence to said second data line:

(a) a 3-bit message type value which specifies a type of message;

(b) a 5-bit unit identification code;

(c) a data type value specifying a data type;

(d) a data byte number value specifying a number of data bytes to follow, the sum of the number of bits in said data byte number value and the number of bits in said data type value being equal to eight;

(e) plural data bytes, the quantity of said data bytes being equal to the number specified by said data byte number value; and

(f) an error-checking value.

3. A method as in claim 2 wherein said data byte number value is five bits in length.

4. A method as in claim 2 wherein said data byte number value is six bits in length.

5. In a digital mobile radio transceiver including radio frequency circuit means for transmitting and receiving radio frequencies, and a digital signal processor connected to control said radio frequency circuit means, a method of communicating between peripheral units and said digital signal processor over a serial data bus having first and second data lines and a service request line, said method comprising the steps of:

(1) detecting seizure of said service request line by a peripheral unit with said digital signal processor;

(2) applying, with said digital signal processor, a poll message to said first data line in response to said detected seizure;

(3) receiving, with said digital signal processor, a preset identification code passed by said peripheral unit over said second data line in response to said applied poll message;

(4) applying, with said digital signal processor, a further poll message including said preset identification code to said first data line in response to receipt of said preset identification code; and

(5) receiving, with said digital signal processor, a further message applied to said second data line responsive to said further poll message.

6. A method of communicating digital data signals between a control head including a first switch having only two alternate positions and a second switch having at least three alternate positions, and a digital mobile radio frequency receiver adapted for connection to said control head via a serial data bus, said method including:

(1) sensing a change in position of said first switch and sensing the absolute position of said first switch;

(2) sensing a change in position of said second switch and sensing the direction of such position change; and

(3) generating a switch position message if said sensing steps (1) and (2) reveal a change in position of either of said first and second switches, said message including;

(a) a plural bit value identifying which of said first and second switches has changed position, and

(b) a single bit value which indicates (b1) the absolute position of said first switch if said sensing step (1) reveals first switch has changed position, and (b2) the direction of the positional change of said second switch of said sensing step (2) reveals said second switch has changed position.

7. A method of communicating digital data signals between (1) a control head including a longitudinal array of discrete single character alpha-numeric displays 1, . . . ,x,x+1, . . . ,N, and (2) a digital mobile radio frequency transceiver adaptable for connection to said control head via a serial data bus, said method including:

(1) receiving an insert character message including the following;

an insert character command,

a value x specifying one of said discrete displays in said array, and

M values each indicating the character to be displayed, M being an integer greater than 1;

(2) scrolling the characters displayed by said displays M positions in a preset direction along said array beginning at the display specified by said value x such that the character formerly displayed by display x is displayed by display x+N;

(z3) displaying the first of said M values with the display specified by said value x; and

(4) displaying the rest of said M values in displays x+1, . . . ,x+M-1.

8. A method of communicating digital data signals between (1) a control head including a loudspeaker and an alarm indicator, and (2) a digital mobile radio frequency transceiver adapted for connection to said control head via a serial data bus, said method including:

receiving a serial audio control command having a message byte including a most significant bit which specifies on/off status and at least one lower order bit specifying one of said loudspeaker and said alarm indicator; and

controlling the one of said loudspeaker and said alarm indicator specified by said lower order bit in accordance with the on/off status specified by said most significant bit.

9. A digital mobile radio transceiver including:

radio frequency circuit means for transmitting and receiving radio frequency signals;

a digital signal processor means connected to control said radio frequency circuit means;

a serial data bus having first and second data lines and a service request line, said bus connected to said processor means;

means connected to said bus for seizing control of said service request line;

means connected to said bus for receiving a poll message passed over said first data line in response to seizure of said service request line;

first applying means connected to said bus for applying a preset identification code to said second data line in response to receipt of said poll message;

means connected to said bus for receiving a further poll message passed over said first data line in response to application of said preset identification code to said second line, said further poll message including said preset identification code;

second applying means connected to said bus for applying a data and/or command message to said second data line in response to receipt of said further poll message; and

means connected to said bus for releasing said service request line.

10. A transceiver as in claim 9 wherein said second applying means includes means for applying the following in sequence to said second data line:

(a) a 3-bit message type value which specifies a type of message;

(b) a 5-bit unit identification code;

(c) a data type value specifying a data type;

(d) a data byte number value specifying a number of data bytes to follow, the sum of the number of bits in said data byte number value and the number of bits in said data type value being equal to eight;

(e) said number of data bytes, the quantity of said data bytes being equal to the number specified by said data byte number value; and

(f) an error-checking value.

11. A transceiver as in claim 10 wherein said data byte number value is five bits in length.

12. A transceiver as in claim 10 wherein said data byte number value is six bits in length.

13. A digital mobile radio transceiver including:

radio frequency circuit means for transmitting and receiving radio frequencies;

a digital signal processor connected to control said radio frequency circuit means;

a serial data bus, having first and second data lines and a service request line, connected to said digital signal processor wherein said digital signal processor includes;

means connected to said data bus for detecting seizure of said service request line by a peripheral unit also connected to said serial data bus;

means connected to said data bus for applying a poll message to said first data line in response to said detected seizure;

means connected to said data bus for receiving a preset identification code passed by said peripheral unit over said second data line in response to said applied poll message;

means connected to said data bus for applying a further poll message including said preset identification code to said first data line in response to receipt of said preset idenitfication code; and

means connected to said data bus for receiving and processing a further message applied to said second data line responsive to said further poll message.

14. A control head adapted for connection to a digital radio transceiver, said control head including:

a first switch having only two alternate positions;

a second switch having at least three alternate positions;

means for sensing a change in position of said first switch and for sensing the absolute position of said first switch;

means for sensing a change in position of said second switch and for sensing the direction of such position change; and

means connected to said first and second sensing means for generating a switch position message if either sensing means reveals a change in position of said first and/or second switches, said message including;

a value identifying which of said first and second switches has changed position, and

a value which indicates the absolute position of said first switch if said first-mentioned sensing means reveals first switch has changed position, and the direction of the positional change of said second switch if said second-mentioned sensing means reveals said second switch has changed position.

15. A digital radio transceiving system comprising:

a control head including a longitudinal array of discrete single character alpha-numeric display means 1, . . . , x, x+1, . . . , N; and

a digital mobile radio frequency transceiver adaptable for connection to said control head;

a serial data bus connected between said control head and said transceiver;

means connected to said data bus for receiving an insert character message including the following;

an insert character command,

a value x specifying one of said discrete displays in said array, and

M values each indicating the character to be displayed, M being an integer greater than 1;

means connected to said receiving means and said control head display means for scrolling the characters displayed by said displays M positions in a preset direction along said array beginning at the display specified by said value x such that the character formerly displayed by display x is displayed by display x+N;

said display means for displaying the first of said M values with the display specified by said value x, and for displaying the rest of said M values in displays x+1, . . . , x+M-1.

16. A digital radio transceiving system comprising:

a control head including a loudspeaker and an alarm indicator;

a digital radio frequency transceiver adapted for connection to said control head via a serial data bus;

means connected to said data bus for receiving a serial audio control command having a message byte including a most significant bit which specifies on/off status and at least one lower order bit specifying one of said loudspeaker and said alarm indicator; and

means connected to said receiving means and operatively coupled to said loudspeaker and to said alarm indicator for controlling the one of said loudspeaker and said alarm indicator specified by said lower order bit in accordance with the on/off status specified by said most significant bit.

17. In a digital mobile communications system including (1) a digital mobile radio frequency transceiver including radio frequency circuit means for transmitting and receiving radio frequency signals and a digital signal processor connected to control said radio frequency circuit means, (2) a peripheral unit, and (3) a serial data bus connecting said digital mobile radio frequency transceiver to said peripheral unit, said serial data bus having first and second data lines and a service request line, a method of communicating between said peripheral unit and said digital signal processor over said serial data bus including the steps of:

(1) seizing control of said service request line with said peripheral unit;

(2) detecting said seizure of said service request line with said processor,

(3) applying, with said processor, a poll message to said first data line in response to said detected seizure,

(4) receiving, with said peripheral unit, said poll message passed over said first data line by said processor in response to seizure of said service request line;

(5) applying a preset identification code to said second data line with said peripheral unit in response to receipt of said poll message;

(6) receiving, with said processor, said preset identification code passed by said peripheral unit over said second data line in response to said applied poll message,

(7) applying a further poll message to said first data line with said processor in response to receipt of said preset identification code, said further poll message including said preset identification code,

(8) receiving, with said peripheral unit, said further poll message passed over said first data line in response to application of said identifiction code to said second line, said further poll message including said preset identification code;

(9) applying a data and/or command message to said second data line with said peripheral unit in response to receipt of said further poll message;

(10) receiving said further message applied to said second data line with said processor; and

(11) releasing said service request line with said peripheral unit.

18. A method as in claim 17 wherein said peripheral unit comprises a control head including a first switch having only two alternate positions and a second switch having at least three alternate positions, and said applying step (9) includes the steps of:

(i) sensing a change in position of said first switch and sensing the absolute position of said first switch;

(ii) sensing a change in position of said second switch and sensing the direction of such position change;

(iii) generating a switch position message if said sensing steps (i) and (ii) reveal a change in position of either of said first and second switches, said message including;

(a) a plural bit value identifying which of said first and second switches has changed position, and

(b) a single bit value which indicates (b1) the absolute position of said switch if said sensing step (i) reveals first switch has changed position, and (b2) the direction of the positional change of said second switch of said sensing step (ii) reveals said second switch has changed position; and

(iv) apply said switch position message to said second data line.

19. A method as in claim 17 wherein said peripheral unit comprises a control head including a longitudinal array of discrete single character alpha-numeric displays 1, . . . ,x,x+1, . . . ,N and said method further includes the steps of:

(i) receiving an insert character message including the following;

an insert character command,

a value x specifying one of said discrete displays in said array, and

M values each indicating the character to be displayed, M being an integer greater than 1;

(ii) scrolling the characters displayed by said displays M positions in a preset direction along said array beginning at the display specified by said value x such that the character formerly displayed by display x is displayed by display x+N;

(iii) displaying the first of said M values with the display specified by said value x; and

(iv) displaying the rest of said M values in displays x+1, . . . ,x+M-1.

20. A method as in claim 17 wherein said peripheral unit comprises a control head including a loudspeaker and an alarm indicator, and said method further includes the steps of:

(i) receiving a serial audio control command having a message byte including a most significant bit which specifies on/off status and at least one lower order bit specifying one of said loudspeaker and said alarm indicator; and

(ii) controlling the one of said loudspeaker and said alarm indicator specified by said lower order bit in accordance with the on/off status specified by said most significant bit.

21. A method of operating a mobile data communications system, said system including a mobile data terminal, a mobile data terminal interface and a digital radio transceiver, said mobile data terminal interface communicating with said transceiver via a first serial data link connected therebetween, said mobile data terminal interface and said mobile data terminal communicating via a further serial data link connected therebetween, said method comprising:

(a) programming said interface including;

(a1) generating at least one control character indicating programming is to occur;

(a2) generating a character n specifying a port;

(a3) generating plural characters b specifying a baud rate;

(a4) generating a character d specifying the number of data bits to be contained in each data byte;

(a5) generating a character s specifying the number of stop bits to terminate each data byte;

(a6) generating a character p specifying the type of parity calculation to be performed;

(a7) generating a character x specifying whether XON/XOFF control is supported,

(a8) generating a character m specifying whether modem control is supported;

(a9) generating a character specifying whether the port specified by said character n is connected to a mobile data terminal or to an automatic vehicular locator;

(a10) generating a character c specifying whether a port different from the port specified by said character n can be enabled for connection to a further mobile data terminal; and

(a11) applying said characters generated by said steps (a1)-(a10) to said mobile data terminal interface via said first serial data link; and

(b) transferring digital data between said mobile data terminal and said mobile data terminal interface over said further serial data link including;

(b1) generating a control character specifying the form of data transfer;

(b2) generating a character e indicating whether said digital data is encrypted;

(b3) generating characters s, d identifying a source and a destination port, respectively;

(b4) generating a character t identifying a type of radio transmission used to convey said digital data;

(b5) generating plural characters identifying radio unit(s) originating and/or to receive said digital data;

(b6) passing said character generated by said steps (b1)-(b5) over said further serial data link; and

(b7) transferring digital data over said first serial data link in the form specified by said control character generated by said step (b1).