Communication system and method

• US 7,920,539 B2
• Filed: 08/26/2004
• Issued: 04/05/2011
• Est. Priority Date: 08/26/2004
• Status: Active Grant

• Current Assignee: HM Electronics Incorporated
• Original Assignee: HM Electronics Incorporated
• Inventors: Hoeptner, Scott, Stanford, Thomas
• Primary Examiner(s): Edouard; Patrick N
• Assistant Examiner(s): Genack; Matthew W
• Application Number:
  US10/928,476
• Publication Number:
  US 20060045063A1
• Time in Patent Office: 2,413 Days
• Field of Search: None
• US Class Current: 370/345
• CPC Class Codes: H04B 7/2643 using time-division multiple access [TDMA] H04B7/2615, H04B7/2618 take precedence
• CPC Class Codes: H04W 84/16 WPBX [Wireless Private Branch Exchange]

Abstract

A system and method is disclosed for allowing communications between a base station and a group of mobile transceivers in a communications network used for a merchant facility.

Claims

1. A drive-up quick service establishment communication system for use by a merchant facility having a building and an external adjacent service lane outside of the building to provide communication among a customer located at the service lane and at least four service personnel located within the building, at least one of the service personnel can be an order taker, comprising:

a single base station disposed within the building;

at least four mobile transceivers disposed within the building for use by the service personnel, sharing a single radio link with the base station to simultaneously communicate in a wireless, digital, full-duplex voice communication manner with each other and with the customer in the service lane;

a service point disposed at the service lane and coupled to the base station for communicating with the mobile transceivers to enable audio communication between the customer in the service lane and the service personnel in the building;

the base station including a single transceiver for providing full-duplex voice communication with the mobile transceivers in a simultaneous full duplex mode of operation using TDMA and a number of transmit/receive time slots;

wherein the base station manages the time slots and routes and combines voice messages to provide a full-duplex party line intercom or full-duplex private line communications or both with the mobile transceivers or between mobile transceivers;

at least one mobile transceiver being capable of initiating a voice transmission during a time slot assigned by the base station upon request of the at least one mobile transceiver on a transmit time to the base station transceiver on a single frequency shared with all mobile transceivers;

wherein the base station routes and combines the voice signal from the at least one mobile transceiver for retransmission to all other mobile transceivers or a specific transceiver selectively;

one or more of the mobile transceivers used for order taking purposes being capable of full-duplex voice communication with the customer and with the other mobile transceivers;

each of the mobile transceivers of the service personnel being capable of serving as an order taking transceiver to communicate with the customer via the service point, and alternatively being capable of receiving voice messages only for listening in full-duplex to the voice communication between order taking transceivers and the service point;

wherein the radio link is a full-duplex time division duplex arrangement; and

whereby the base station provides selectively a first full-duplex channel of pa line communication between the service the mobile transceivers and a second full-duplex channel of party line communication between the mobile transceivers only to the exclusion of the service point.

2. The system of claim 1, wherein a time slot of the TDMA arrangement is allocated for broadcast of mixed audio information obtained from all transmitting mobile transceivers.

3. The system of claim 1, wherein the same information is transmitted during two separate TDMA time slots, and at two different frequencies and received and a determination made as to the most reliable information of the two time slots.

4. The system of claim 1, wherein the radio link arrangement is frequency hopping spread-spectrum and TDD communication between the base station and the mobile transceivers.

5. The system of claim 1, wherein the base station causes a selection of a mobile transceiver and causes the making of a full duplex connection with any one other mobile transceiver to establish a private communication isolated from other communication sinks.

6. The system of claim 5, wherein the initiating mobile transceiver controls the communication link such that the initiating mobile transceiver can disconnect the communication link at any time.

7. The system of claim 5, wherein either the initiating mobile transceiver or the selected mobile transceiver can disconnect the communication link at any time.

8. The system of claim 1, wherein the base station causes routing of audio from any mobile transceiver to a secondary speaker at a remote location and electrically coupled to the base station.

9. The system of claim 1, further including an external device coupled to the base station for generating audio messages and transmitting said audio messages to the base station;

and further including means for audio routing and control functions transacted between said external device and the base station for use within the base station and transmission to the mobile transceivers; and

means for receiving controls and status from mobile transceivers transacted between the base station and the external device.

10. The system of claim 1, wherein analog voice signals or digital data or both are communicated between the base station and at least one mobile transceiver.

11. The system of claim 9, wherein the external device, is a computer for providing said digital data.

12. The system of claim 9, further including means for providing said digital data.

13. The system of claim 1, wherein at least one mobile transceiver is connected as receive only to the base station and receives all other communications as a group broadcast.

14. The system of claim 13, wherein said at least one mobile transceiver can also connect full duplex for transmission to the base station or to other mobile transceiver or both.

15. The system of claim 1, wherein all communications are encrypted to prevent unauthorized communications.

16. The system of claim 1, wherein the mobile transceivers provide audible voice messages to give status to a mobile transceiver service person.

17. The system of claim 1, wherein the base station includes at least two antennas mounted apart for purposes of receiving and transmitting and wherein the base station makes a decision as to which antenna to use based on signal strength at the beginning a receive time slot.

18. The system of claim 1, wherein the mobile transceivers include at least two antennas for purposes of receiving and transmitting that are mounted apart from one another wherein the mobile transceiver decides which antenna to use based on signal strength at the beginning a receive time slot.

71. The system of claim 1, wherein at least two of the mobile transceivers being capable of initiating voice communication simultaneously with the other mobile transceivers.

72. The system of claim 1, wherein at least one of the mobile transceivers being capable of initiating a private voice communication with one of the other mobile transceivers.

73. The system of claim 1, further including

a second group of mobile transceivers for a second set of service personnel, and

a second service point coupled to the base station for communicating with at least the second group of mobile transceivers to enable communication between a second customer and at least the second set of service personnel.

74. The system of claim 73, wherein the at least one of the second group mobile transceivers used for order taking purposes with the second customer being capable of voice communication with the second customer and with all of the other mobile transceivers.

75. The system of claim 74, wherein each of the mobile transceivers of the second set of service personnel being capable of receiving voice messages only for listening to the voice communication between the second order taking transceiver and the second service point and being, capable of voice communication with all of the other mobile transceivers.

19. A drive-up quick service establishment communication system for use by a merchant facility having a building and an external adjacent service lane outside of the building to provide communication among a customer located at the service lane and service personnel located within the building, at least one of the service personnel can be an order taker, comprising:

a single base station disposed within the building;

a service point disposed at the service lane and coupled to the base station;

a group of mobile transceivers disposed within the building for use by the service personnel, sharing a single radio link with the base station to simultaneously communicate in a wireless, digital, full-duplex voice communication manner with each other;

the base station including a single transceiver for providing voice communication with the group of mobile transceivers in a simultaneous full duplex mode of operation using TDMA and a number of transmit/receive time slots;

wherein the base station manages the time slots and routes and combines voice messages to provide a party line intercom or private line communications or both with the group of mobile transceivers or between mobile transceivers;

one or more mobile transceiver being capable of initiating a voice transmission during a time slot assigned by the base station upon request of the at least one mobile transceiver on a transmit time to the base station transceiver on a single frequency shared with all mobile transceivers;

wherein the base station routes and combines the voice signal from the at least one mobile transceiver for retransmission to all other mobile transceivers or a specific transceiver selectively;

at least one of the mobile transceivers used for order taking purposes being capable of full-duplex voice communication with the customer and with the other mobile transceivers;

each of the mobile transceivers of the service personnel being capable of serving as an order taking transceiver to enable full-duplex audio communication with the customer via the service point, and alternatively being capable of receiving full-duplex voice messages only for listening to the voice communication between order taking transceivers and the service point; and

wherein the service point includes a speaker and a microphone disposed physically at a remote location and connected to the base station for purposes of communicating with the customer; and

whereby the base station provides selectively a first full-duplex channel of line communication between the service point and the mobile transceivers and a second full-duplex channel of party line communication between the mobile transceivers only to the exclusion of the service point.

20. The system of claim 19, wherein a time slot of said TDMA method is allocated for broadcast of mixed audio information obtained from the remote microphone location and all transmitting mobile transceivers.

21. The system of claim 19, wherein the radio link is frequency hopping spread-spectrum and TDD communication between the base station and the group of mobile transceivers.

22. The system of claim 19, wherein the base station routes communication between a mobile transceiver, all other mobile transceivers, and the speaker and microphone coupled to the base station.

23. The system of claim 19, wherein the base station causes communication to be routed between a mobile transceiver and all other mobile transceivers in the second channel while excluding the speaker and microphone coupled to the base station.

24. The system of claim 19, further including a secondary speaker, and wherein the base station causes the audio to be routed from the microphone coupled to the base station and/or audio received from any mobile transceiver to a secondary speaker at a remote location and electrically coupled to the base station.

25. The system of claim 19, further including a secondary speaker, and wherein the base station causes the presence of a customer to be detected at a service point so that when detected, the base station opens a broadcast communication connection and routes audio to the mobile transceivers and a secondary speaker or both, when appropriately enabled.

26. The system of claim 25, wherein communication between the service point speaker and microphone has priority over other communications, and the base station terminates other mobile transceiver communications as necessary to allow communication with at least one mobile transceiver.

27. The system of claim 25, wherein in response to customer presence detection, communication between the service point speaker and microphone can be routed by the base station to at least one mobile transceiver without the need for the service person at the mobile transceiver to take any physical action in order to respond;

and, when the customer is no longer detected, the connection to the mobile transceiver automatically returns to the standby “

listen”

condition without any physical intervention of the mobile transceiver service person.

28. The system of claim 25, wherein the customer presence detection generates a logic signal that is available to be used for other unspecified purposes external to the base station.

45. The system of claim 19, wherein the radio link is a direct-sequence spread-spectrum and TDD communication between the base station and the group of mobile transceivers.

29. A drive-up quick service establishment communication system for use by a merchant facility having a building and at least two external adjacent service lanes outside of the building to provide communication among customers located at the service lanes and service personnel located within the building, at least one of the service personnel can be an order taker, comprising:

a single base station disposed within the building;

a first service point disposed at one of the service lanes and coupled to the base station to enable full-duplex audio communication between a customer in the one of the service lanes and the service personnel in the building;

a second service point disposed at another of the service lanes and coupled to the base station to enable full-duplex audio communication between another customer in the another of the service lanes and the service personnel in the building;

a group of mobile transceivers disposed within the building for use by the service personnel, sharing a single radio link with the base station to simultaneously communicate in a wireless, digital, full-duplex voice communication manner with each other;

the base station including a single transceiver for providing voice communication with the group of mobile transceivers in a simultaneous full duplex mode of operation using TDMA and a number of transmit/receive time slots;

wherein the base station manages the time slots and routes and combines full-duplex voice messages to provide a party line intercom or private line communications or both with the group of mobile transceivers or between mobile transceivers;

at least one mobile transceiver being capable of initiating a full-duplex voice transmission during a time slot assigned by the base station upon request of the at least one mobile transceiver on a transmit time to the base station transceiver on a single frequency shared with all mobile transceivers;

wherein the base station routes and combines the full-duplex voice signal from the at least one mobile transceiver for retransmission to all other mobile transceivers or a specific transceiver selectively;

at least one of the mobile transceivers used for order taking purposes being capable of full-duplex voice communication with at least one of the customers and with the other mobile transceivers;

each of the mobile transceivers of the service personnel being capable of serving as an order taking transceiver to communicate with the customers at the services points, and alternatively being capable of receiving voice messages only for listening to the full-duplex voice communication between order taking transceivers and the service points; and

wherein the first service point includes a first speaker and a first microphone disposed physically at a remote location and connected to the base station for purposes of communicating with the first service point;

wherein the second service point includes a second speaker and a second microphone disposed physically at another remote location and connected to the base station for purposes of communicating with the second service point; and

whereby the base station provides selectively a first full-duplex channel of party line communication between the service point and the mobile transceivers and a second full-duplex channel of party line communication between the mobile transceivers only to the exclusion of the service point.

30. The system of claim 29, wherein a time slot of said TDMA method is allocated for broadcast of mixed audio information obtained from the first remote microphone location and all transmitting mobile transceivers, and a second time slot of said TDMA method is allocated for broadcast of mixed audio information obtained from the second remote microphone location and all transmitting mobile transceivers.

31. The system of claim 29, wherein the radio link is frequency hopping spread-spectrum and TDD communication between the base station and the group of mobile transceivers.

32. The system of claim 29, wherein the base station causes the detection of the presence of a customer at the first service point so that when detected, the base station opens a first broadcast communication connection and routes audio from the first service point to the mobile transceivers assigned;

and wherein the base station causes the detection of the presence of a customer at the second service point so that when detected, the base station connects a second broadcast communication link and routes audio from the second service point to the mobile transceivers assigned to the second service point.

33. The system of claim 32, further including first and second speakers, and wherein the base station routes audio from the first and second service points to the mobile transceivers assigned and respective first and second speakers, or both of them, when enabled.

34. The system of claim 32, further including a slave base station.

35. The system of claim 32, wherein communication between the speaker and microphone from each service point has priority over other communications and the base station terminates other mobile transceiver communications as necessary to allow communication of each service point with at least one mobile transceiver.

36. The system of claim 32, wherein in response to customer presence detection at the first service point, communication between the first speaker and first microphone can be routed by the base station to at least one mobile transceiver without the need for the service person at the mobile transceiver to take any physical action in order to respond;

and, when the customer is no longer detected, the connection to the mobile transceiver automatically returns to the standby “

listen”

condition without any physical intervention of the mobile transceiver service person.

37. The system and method of claim 32, wherein the customer presence detection from either or both service points generates a logic signal that is available to be used for other unspecified purposes external to the base station.

38. The system and method of claim 32, wherein in response to a customer presence detection at the second service point, communication between the second service point speaker and microphone can be routed by the base station to at least one mobile transceiver without the need for the service person at the mobile transceiver to take any physical action in order to respond;

and, when the customer is no longer detected, the connection to the mobile transceiver automatically returns to the standby “

listen”

condition without any physical intervention of the portable terminal user.

39. The system and method of claim 29, wherein mobile transceiver service persons communicating with the first service point are isolated from mobile transceivers communicating with the second service point.

40. The system of claim 29, wherein mobile transceivers enable a mobile transceiver service person to connect with either one of the two service points, and to switch between the two different service point connection communication links.

41. The system of claim 34, wherein the first mentioned base station causes communications to be routed between a mobile transceiver communicating with the first service point and all other mobile transceivers excluding the first service point;

and, the slave base station causes communications to be routed between a mobile transceiver communicating with the second service point and all other mobile transceivers excluding the second service point.

42. The system of claim 34, wherein the first mentioned base station causes communications to be routed between a mobile transceiver communicating with the first service point and only the other mobile transceivers that are in communication with the first mentioned base station and excluding the first service point;

and, the slave base station causes communications to be routed between a mobile transceiver communicating with the second service point and only the other mobile transceivers that are in communication with the slave base station and excluding the second service point.

43. The system of claim 34 wherein the first mentioned and slave base stations provide communication links to the respective first and second service points.

44. The system of claim 29, wherein the radio is direct-sequence spread-spectrum and TDD communication between the base station and the group of mobile transceivers.

46. The system of claim 29, wherein the radio link is a direct-sequence spread-spectrum and TDD communication between the base station and the group of mobile transceivers.

47. The system of claim 29, further including a slave base station, and wherein the first-mentioned and the slave base stations share the single transceiver for communicating with the mobile transceivers.

48. A drive-up quick service establishment communication method for use by a merchant facility having a building and an external adjacent service lane outside of the building to provide communication among a customer located at the service lane and service personnel located within the building, at least one of the service personnel can be an order taker, comprising:

establishing a service point communication link between a service point disposed at the service lane and a single base station disposed within the building;

establishing a wireless communication link between the base station and a service person using a mobile transceiver to link with the service point communication link to enable the service point and the service person to communicate in an audio full-duplex manner for initiating a transaction;

establishing a wireless full-duplex communication link between the base station and another service person using another mobile transceiver to link with the communication link between the service point and the other service person so that both service people and the service point can communicate in an audio manner with one another simultaneously,

wherein the base station includes a single transceiver for providing voice communication with the mobile transceivers in a simultaneous full-duplex mode of operation using TDMA and a number of transmit/receive time slots;

wherein the base station manages the time slots and routes and combines voice messages to provide a party line intercom or private line communications or both with the group of mobile transceivers or between mobile transceivers;

wherein at least one mobile transceiver is capable of initiating a full-duplex voice transmission during a time slot assigned by the base station upon request of the at least one mobile transceiver on a transmit time to the base station transceiver on a single frequency shared with all mobile transceivers;

wherein the base station routes and combines the full-duplex voice signal from the at least one mobile transceiver for retransmission to all other mobile transceivers or a specific transceiver selectively;

at least one of the mobile transceivers used for order taking purposes being capable of full-duplex voice communication with the customer and with the other mobile transceivers;

each of the mobile transceivers of the service personnel being capable of serving as an order taking transceiver to communicate in full-duplex with the customer via the service point, and alternatively being capable of receiving voice messages only in full-duplex for listening to the voice communication between order taking transceivers and the service point;

wherein the radio link is a time division duplex arrangement; and

whereby the base station provides selectively a first full-duplex channel of party line communication between the service point and the mobile transceivers, and a second full-duplex channel of party line communication between the mobile transceivers only to the exclusion of the service point.

49. A drive-up quick service establishment communication method for use by a merchant facility having a building and an external adjacent service lane outside the building to provide communication among a customer located at the service lane and service personnel located within the building, at least one of the service personnel can be an order taker, comprising:

establishing an service point full-duplex communication link between a service point disposed at the service lane and a single base station disposed within the building;

establishing a wireless full-duplex communication link between the base station and a service person using a mobile transceiver to link with the service point communication link to enable the service point and the service person to communicate in an audio manner for initiating a transaction;

establishing a full-duplex wireless communication link between the base station and another service person using another mobile transceiver to enable said another service person to broadcast an audio communication to other service persons independently of the communication between the service point and the service person;

establishing full-duplex broadcast communication links between the base station and other service person mobile transceivers to enable said other service person to communicate in an audio manner simultaneously with the other service persons,

wherein the base station includes a single transceiver for providing voice communication with the mobile transceivers in a simultaneous full duplex mode of operation using TDMA and a number of transmit/receive time slots;

wherein the base station manages the time slots and routes and combines full-duplex voice messages to provide a party line intercom or private line communications or both with the group of mobile transceivers or between mobile transceivers;

wherein at least one mobile transceiver is capable of initiating a full-duplex voice transmission during a time slot assigned by the base station upon request of the at least one mobile transceiver on a transmit time to the base station transceiver on a single frequency shared with all mobile transceivers;

wherein the base station routes and combines the full-duplex voice signal from the at least one mobile transceiver for retransmission to all other mobile transceivers or a specific transceiver selectively;

at least one of the mobile transceivers used for order taking purposes being capable of full-duplex, voice communication with the customer and with the other mobile transceivers;

each of the mobile transceivers of the service personnel being capable of serving as an order taking transceiver to communicate in full-duplex with the customer via the service point, and alternatively being capable of receiving voice messages only for listening to the full-duplex voice communication between order taking transceivers and the service point;

wherein the radio link is a time division duplex arrangement; and

whereby the base station provides selectively a first full-duplex channel of party between the service point and the mobile transceivers, and a second full-duplex channel of party line communication between the mobile transceivers only to the exclusion of the service point.

50. A drive-up quick service establishment communication method for use by a merchant facility having a building and an external adjacent service lane outside of the building to provide communication among a customer located at the service lane and service personnel located within the building, at least one of the service personnel can be an order taker, comprising:

establishing a service point full-duplex communication link between a service point disposed at the service lane and a single base station disposed within the building;

establishing a wireless full-duplex communication link between the base station and a service person using a mobile transceiver to link with the service point communication link to enable the service point and the service person to communicate in an audio full-duplex manner for initiating a transaction; and

establishing a wireless independent full-duplex communication link between at least two other service persons using other mobile transceivers to enable said other service persons to communicate in an audio manner with one another independently of the communication between the service person and the service point user,

wherein the base station includes a single transceiver for providing voice communication with the mobile transceivers in a simultaneous full duplex mode of operation using TDMA and a number of transmit/receive time slots;

wherein the base station manages the time slots and routes and combines full-duplex voice messages to provide a party line intercom or private line communications or both with the group of mobile transceivers or between mobile transceivers;

at least one mobile transceiver being capable of initiating a full-duplex voice transmission during a time slot assigned by the base station upon request of the at least one mobile transceiver on a transmit time to the base station transceiver on a single frequency shared with all mobile transceivers;

wherein the base station routes and combines the full-duplex voice signal from the at least one mobile transceiver for retransmission to all other mobile transceivers or a specific transceiver selectively;

at least one of the mobile transceivers used for order taking purposes being capable of full-duplex voice communication with the customer and with the other mobile transceivers;

each of the mobile transceivers of the service personnel being capable of serving as an order taking transceiver to communicate in full-duplex with the customer via the service point, and alternatively being capable of receiving voice messages only for listening in full-duplex to the voice communication between order taking transceivers and the service point; and

whereby the base station provides selectively a first full-duplex channel of party line communication between the service point and the mobile transceivers, and a second full-duplex channel of party line communication between the mobile transceivers only to the exclusion of the service point.

51. A method of claim 50, wherein the establishing of the communication links includes communicating analog voice signals or digital data or both.

52. A method of claim 51, further including providing audible voice messages at the mobile transceivers to provide status or instructions to the service person.

53. A method of claim 50, further including deciding which one of a plurality of antennas to use based on signal strength at the beginning of the receive time slot.

54. A method of claim 50, where the communication link is frequency hopping spread spectrum and TDD communication.

55. A method of claim 50, further including routing communication between a mobile transceiver, all other mobile transceivers, and the service point.

56. A method of claim 50, wherein the base station causes communication to be routed between a mobile transceiver and all other mobile transceivers while excluding the speaker and microphone coupled to the base station.

57. A method of claim 50, further including causing the presence of a customer to be detected, and establishing a broadcast communication link to be established in response to the customer being detected.

58. A method of claim 57, wherein in response to customer presence detection, communication between the service point speaker and microphone can be routed by the base station to at least one mobile transceiver without the need for the service person at the mobile transceiver to take any physical action in order to respond;

and, when the customer is no longer detected, the connection to the mobile transceiver automatically returns to the standby “

listen”

condition without any physical intervention of the mobile transceiver service person.

59. A method of claim 50, wherein the establishing of the links includes a data channel.

60. A method of claim 59, further including controlling data on the data channel.

61. A method of claim 59, further including establishing a link to an external data system.

62. A method of claim 50, further including repeating messages to the service point or other speakers when a customer is present.

63. A method of claim 50, further including initiating a speed team mode of operation.

64. A method of claim 50, further including registering a mobile transceiver with the base station.

65. A method of claim 50, further including generating a customer-present signal when a customer is present at the service point.

66. A method of claim 50, further including a second service point, establishing communication links between a mobile transceiver and either one of the service points selectively.

67. A method of claim 50, further including reducing inbound audio signals to the base station to help reduce feedback by using voice activated attenuation.

68. A method of claim 50, further including providing automatic volume control and noise cancellation.

69. A drive-up quick service establishment communication system for use by a merchant facility having a building and an external adjacent service lane outside the building to provide communication among a customer located at the service lane and service personnel located within the building, at least one of the service personnel can be an order taker, comprising:

a single base station disposed within the building;

a group of mobile transceivers disposed within the building for the service personnel;

a service point disposed at the service lane and coupled to the base station for communicating in an audio full-duplex manner with the customer;

the base station including a single transceiver for providing full-duplex voice communication with the mobile transceivers;

at least one of the mobile transceivers used for order taking purposes being capable of full-duplex voice communication with the customer and with the other mobile transceivers;

each of the mobile transceivers of the service personnel being capable of receiving full-duplex voice messages only for listening to the voice communication between the order taking transceiver and the service point and being capable of voice communication with the other mobile transceivers; and

wherein at least two of the mobile transceivers are each capable of initiating full-duplex voice communication simultaneously with the other mobile transceivers; and

whereby the base station provides selectively a first full-duplex channel of party line communication between the service point and the mobile transceivers and a second full-duplex channel of party line communication between the mobile transceivers only to the exclusion of the service point.

70. A drive-up quick service establishment communication system for use by a merchant facility having a building and an external adjacent service lane outside of the building to provide communication among a customer located at the service lane and service personnel located within the building, at least one of the service personnel can be an order taker, comprising:

a single base station disposed within the building;

a group mobile transceivers disposed within the building for the service personnel;

a service point disposed at the service lane and coupled to the base station for full-duplex communicating in an audio manner with the customer;

the base station including a single transceiver for providing full-duplex voice communication with the mobile transceivers;

at least one of the mobile transceivers used for order taking purposes being capable of full-duplex voice communication with the customer and with the other mobile transceivers;

each of the mobile transceivers of the service personnel being capable of receiving full-duplex voice messages only for listening to the voice communication between the order taking transceiver and the service point and being capable of voice communication with the other mobile transceivers; and

at least one of the mobile transceivers being capable of initiating a private voice communication with one of the other mobile transceivers; and

whereby the base station provides selectively a first full-duplex channel of party line communication between the service point and the mobile transceivers and a second full-duplex channel of party line communication between the mobile transceivers only to the exclusion of the service point.