A local communication system for the integrated transmission of speech and digital data

Claim 2

Station apparatus as claimed in Claim 2, wherein the microprocessor is arranged to recognise the address of each received message and only pass data received by the serial-to-parallel converter to an appropriate data path output or to the timing detector if the message is addressed to the station apparatus.

Claim 3

Station apparatus as claimed in Claim 3, wherein the speech receiving and transmitting means include speech demodulating means operable under the control of said timing signal (or a signal derived therefrom) for demodulating that part of the signal on the first signal path which is associated with the channel allocated to the station apparatus, and means operable under control of the timing signal (or a signal derived therefrom) for deriving a digitally-coded speech signal in respect of speech to be transmitted from the station apparatus and inserting that signal into the channel on the first signal path allocated to the station apparatus.

Claim 4

Station apparatus as claimed in Claim 4, and further including a memory for storing incoming or outgoing data, a parallel input/output unit and a serial input/output unit all connected by the data bus to the microprocessor.

Claim 5

Station apparatus as claimed in any one of Claims 2 to 5, wherein the serial-to-parallel converter is arranged to operate as a parallel-to-serial converter when digital data is to be transmitted, the serial output of the converter being connected to a coder for transmission to the second signal path.

Claim 6

Station apparatus as claimed in Claim 6, and including a clock signal generator for supplying a clock signal to the coder in parallel with the serial data from the converter.

Claim 7

Station apparatus as claimed in Claim 6, wherein the clock signal generator is part of the microprocessor.

Claim 8

Station apparatus as claimed in any one of the preceding claims, and including a control unit connected to the timing detector and to the convertor, the control unit in operation receiving a signal from a carrier sensing unit which acts as the means for detecting the presence of data on the second signal path, and of a signal from the timing detector indicating the detection of the synchronising channel, the control unit providing as one output a signal for inhibiting the transmission of digital data to the second signal path unless there is both absence of data on the second signal path and the presence of the synchronising channel on the first signal path has been detected.

Claim 9

Station apparatus substantially as hereinbefore described with reference to the accompanying drawing.

Claim 10

A two-way communication system for the integrated transmission of speech and data comprising a first physical signal path for the transmission in one direction of a signal which provides a plurality of circuit-switched channels combined in time division multiplex and which contains channel synchronising information and a second physical signal path which follows substantially the same route as the first path and which is for the broadcast transmission of digital data in packet form, the first and second paths having a plurality of ports connected thereto along the length thereof, and at least one of said ports being connected to station apparatus as claimed in any one of the preceding claims.

Claim 11

A communication system as claimed in Claim 11, wherein each port includes an amplifier for amplifying a digital data signal being transmitted onto the second path from a station apparatus connected to the port the operation of the amplifier being enabled or disabled by a signal generated by said control means so as to avoid the possibility of ·'cσllision'

Claim 12

A communication system as claimed in either Claim 11 or Claim 12, wherein at each port the first signal path includes relay means controlled by said control unit, the relay means closing in response to power failure of the associated station apparatus so as to complete the first signal path as far as the rest of the communication system is concerned.

Claim 13

A communication system as claimed in any one of Claims 11 to 13, wherein the first signal path includes two different channels for transmission to and from a station using an appropriate time division multiple access line code, and wherein the or each station apparatus includes delay means for introducing a predetermined delay after receipt of the synchronising channel and before permitting the transmission of a packet of data.