Method for processing telephone signals supplied by an analog telephone terminal and data supplied by a data terminal

1. A method of handling telephone signals supplied by an analog telephone set and data supplied by a data terminal in the subscriber line circuit of a digital telephone switching system used at least in subregions for data transmission, which comprises:

connecting a telephone set and a data terminal to a subscriber line circuit of a digital telephone switching system through a common analog subscriber line;

subjecting data outgoing to the digital telephone switching system to an analog/digital conversion at a sampling rate above a sampling rate required for telephone information such that the data originating from the data terminal is not subject to the same restrictions as the signals originating from the analog telephone set; and

according to a digital coding to analog conversion, data incoming from the digital telephone switching system using a linear characteristic; and feeding data originating from and handled by the data terminal directly to a data transmission network.

2. The method according to claim 1 , which further comprises modulating data signals supplied for transmission on the subscriber line at a frequency above a frequency band authorized for transmission of telephone signals.

3. The method of handling telephone signals according to claim 1 , which further comprises using a linear analog/digital conversion characteristic such that the data originating from the data terminal is not subject to the same restrictions as the signals originating from the analog telephone set.

4. A subscriber line circuit for handling telephone signals supplied by an analog telephone set and data supplied by a data terminal in a subscriber line circuit of a digital telephone switching system used at least in subregions for data transmission, comprising:

a telephone set for producing telephone signals;

a data terminal having a modem for producing data signals;

an analog subscriber line, said telephone set (Tela, Telb) and said data terminal directly connected to a subscriber line circuit of a digital telephone switching system through said analog subscriber line;

an analog/digital converter having a sampling rate above a sampling rate required for telephone information, said analog/digital converter:

connected to said telephone set and said data terminal;

receiving said telephone signals and said data signals; and

producing digital signals according to the sampling rate such that the data originating from the data terminal is not subject to the same restrictions as the signals originating from the analog telephone set; and

a digital signal processor reducing signals incoming from the digital telephone switching system to a transmission bit rate for telephone transmission and simultaneously coding said telephone signals according to a nonlinear characteristic.

5. The subscriber line circuit according to claim 4 , wherein said digital signal processor emits digital signals, and including:

a data network; and

a digital interface connected to said digital signal processor, said digital interface:

conveying digital signals representing data signals emitted by said digital signal processor to said data network; and

conveying to said digital signal processor digital signals coming from said data network intended for said data terminal.

6. The subscriber line circuit according to claim 4 , wherein the digital signals use a linear analog/digital conversion characteristic such that the data originating from the data terminal is not subject to the same restrictions as the signals originating from the analog telephone set.

7. In a digital telephone switching system used at least in subregions for data transmission, a subscriber line circuit, comprising:

a telephone set for producing telephone signals;

a data terminal having a modem for producing data signals;

an analog subscriber line, said telephone set and said data terminal directly connected to the digital telephone switching system through said analog subscriber line;

an analog/digital converter having a sampling rate above a sampling rate required for telephone information, said analog/digital converter:

connected to said telephone set and said data terminal;

receiving said telephone signals and said data signals; and

producing digital signals; and

a digital signal processor reducing signals incoming from the digital telephone switching system to a transmission bit rate for telephone transmission and simultaneously coding said telephone signals according to a nonlinear characteristic such that the data originating from the data terminal is not subject to the same restrictions as the signals originating from the analog telephone set.

8. The subscriber line circuit according to claim 7 , wherein said digital signal processor emits digital signals, and including:

a data network; and

a digital interface connected to said digital signal processor, said digital interface:

conveying digital signals representing data signals emitted by said digital signal processor to said data network; and

conveying to said digital signal processor digital signals coming from said data network intended for said data terminal.

9. The digital telephone switching system according to claim 7 , wherein the telephone signals are coded also using a linear characteristic for the data originating from the data terminal such that the data originating from the data terminal is not subject to the same restrictions as the signals originating from the analog telephone set.