Ringing signal transmission system for radiotelephone system

• US 4,574,164 A
• Filed: 09/19/1984
• Issued: 03/04/1986
• Est. Priority Date: 09/26/1983
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Orikasa, Hiromi
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/652,296
• Time in Patent Office: 531 Days
• Field of Search: 179/2 E-2 EC
• US Class Current: 455/458
• CPC Class Codes: H04W 84/02 Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
• CPC Class Codes: H04W 84/04 Large scale networks; Deep hierarchical networks

Abstract

A base station (coast station) of such a radiotelephone system as a maritime mobile radiotelephone system is connected to a telephone exchange of a public telecommunication network. A ringing signal from a subscriber'"'"'s station of the telecommunication network which is connected to the exchange is transmitted to an end station (ship station) of the radiotelephone system by way of the line concentrator and a radio section between the base and end stations. When a false calling tone signal is sent from a tone signal delivery circuit included in the line concentrator to an end station for a predetermined short period of time upon completion of a connection between the exchange and the end station, with no regard to a ringing signal from the exchange, a subscriber'"'"'s telephone at the end station produces a calling tone. Thereafter, the line concentrator delivers a calling tone signal in synchronism with a ringing signal from the exchange. The telephone at the terminal station, therefore, produces a tone immediately after a connection has been completed, so that the subscriber at the end station is prevented from off-hooking during an interruption time of a calling tone to cause collision of receipt of a call and origination of a call.

Claims

1. In a radiotelephone system comprising a telephone switching network which includes a telephone exchange for sending a ringing signal, at least one base station connected to the telephone switching network, and a plurality of end stations each being provided with a telephone, wherein a multi-channel access radio section is set up between the base station and each of the end stations and the telephone at each of the end stations produces a calling tone in synchronism with a ringing signal after the ringing signal from the telephone exchange is transmitted over the radio section, a ringing signal transmission system comprising:

trunk circuits connected between the base station and the telephone exchange in correspondence with channels of the radio section; and

a tone signal generator circuit called by the telephone exchange to generate a calling tone signal for a predetermined period of time immediately after the completion of a connection of the radio section for a call to be received by one of the end stations, with no regard to a ringing signal to be delivered from the telephone exchange, said calling tone signal being transmitted to said one end station.

2. A ringing signal transmission system as claimed in claim 1, in which the trunk circuits constitute trunk circuits of a line concentrator which is interposed between the telephone switching network and the base station.