Method of distributing tone and alerting signals in a TDM communication system

Claim 3

The method according to claim 1, characterized by sampling and coding the common basic tone of all tone signals centrally, and distributing the code words representing the samples over a time division multiplex channel provided particularly for this purpose, to which all terminals always have access.

Claim 4

The method according to claim 1, characterized by transmitting a cadence control word over the common channel in every n-th frame, the ratio n between the sampling period of the cadencing signals and the multiplex frame period being chosen such that the period of any of the cadencing signals is an integer multiple of the frame sampling period.

Claim 5

The method according to claim 1, characterized by distributing the cadence control words over a common time-division multiplex channel which is designed to convey messages comprising a data unit and an associated address, and accompanying each cadence control word during transmission with a universal address valid for all terminals.

Claim 6

The method according to claim 1 characterized by providing a local signal generator and using the cadencing information for the ringback tone in a called terminal to switch on and off the local signal generator in such a way that the required ringing signal is obtained.

Claim 7

The method accoRding to claim 2 characterized by providing and setting control switch means in a terminal to a tone signal to be received; providing a bistable cadence switch in the terminal and, each time a cadence control word is received by the terminal, resetting said bistable cadence switch and then either leaving it in its first state or setting it to its second state, depending on that sample bit of the received cadence control word, which corresponds to the tone signal to which the control switch means are set; providing digital-to-analog conversion means for voice signals and an electro-acoustic transducer for the same in the terminal, operable whenever the bistable cadence switch is in its second state, and transferring basic tone samples received by the terminal to said conversion means.

Claim 8

The method according to claim 4 characterized by providing and setting control switch means in a terminal to a tone signal to be received; providing a bistable cadence switch in the terminal and, each time a cadence control word is received by the terminal, resetting said bistable cadence switch and then either leaving it in its first state or setting it to its second state, depending on that sample bit of the received cadence control word, which corresponds to the tone signal to which the control switch means are set; providing digital-to-analog conversion means for voice signals and an electro-acoustic transducer for the same in the terminal, operable whenever the bistable cadence switch is in its second state, and transferring basic tone samples received by the terminal to said conversion means.

Claim 9

In a time-division multiplex communication system in which a plurality of terminals is connected to lines over which data are transferred in periodic time frames each comprising a plurality of time slots at least one of which is available for the transmission of signaling data, and binary sample values of the cadencing signals of all tone and alerting signals are distributed in signaling time slots in regular intervals to all terminal devices, a terminal device comprising: means for recognizing received command data identifying a selected type of tone or alerting signal to be received by that terminal device, means responsive to the recognizing means for storing an indication of said type of tone or alerting signal to be received, means for applying received binary sample values of cadencing signals to first gating means which are responsive to output signals of said storing means to gate a selected one of the binary sample values corresponding to the tone or alerting signal to be received, means for reproducing a cadencing signal from the output signal of said first gating means, and second gating means for gating a basic tone signal under control of said reproduced cadencing signal.

Claim 10

In a time-division multiplex communication system in which a plurality of terminals is connected to lines over which data are transferred in periodic time frames each comprising a plurality of time slots at least one of which is available for the transmission of signaling data, and binary sample values of the cadencing signals of all tone and alerting signals are distributed in signaling time slots in regular intervals to all terminal devices, a terminal device comprising: means for recognizing received command data identifying a selected type of tone or alerting signal to be received by that terminal device, means responsive to the recognizing means for storing an indication of said type of tone or alerting signal to be received, means for applying received binary sample values of cadencing signals to first gating means which are responsive to output signals of said storing means to gate a selected one of the binary sample values corresponding to the tone or alerting signal to be received, means for reproducing a cadencing signal from the output signal of said first gating means, and second gating means for gating a basic tone signal under control of said reproduced cadencing signal.

Claim 11

In a time-division multiplex communication system in which a plurality of terminals are provided for receiving data representations transmitted in cyclic frames, and binary sample values of the cadencing signals of all tone and alerting signals and of their basic tone are distributed in regularly appearing time slots of the frames, a terminal device comprising: signal storage means and means responsive to the contents thereof for regenerating a selected one of the cadencing signals from received binary sample values, and means responsive to the regenerated cadencing signal and to received binary sample values of the basic tone to regenerate a selected complete tone or alerting signal.

Claim 12

In a time-division multiplex communication system in which a plurality of terminals are provided for receiving data representations transmitted in cyclic frames, and binary sample values of the cadencing signals of all tone and alerting signals and of their basic tone are distributed in regularly appearing time slots of the frames, a terminal device comprising: signal storage means and means responsive to the contents thereof for regenerating a selected one of the cadencing signals from received binary sample values, and means responsive to the regenerated cadencing signal and to received binary sample values of the basic tone to regenerate a selected complete tone or alerting signal.