Telecommunications system including transmultiplexer installed between digital switch and optical signal transmission fiber

A telecommunications system, comprising:

• a central office location;
• a plurality of telephone subscriber locations;
• a plurality of optical fibers, each extending between said central office location and a respective one of said telephone subscriber locations, said optical fibers for guiding optical telephone signals between said central office and said subscriber locations;
• said optical telephone signals corresponding to a plurality of analog transmitting channels and a like plurality of analog receiving channels between each of said telephone subscriber locations and said central office location, said optical telephone signals also including signalling information;
• and
• switching means at said central office location and responsive to said optical telephone signals for enabling said analog transmitting channels to be selectively coupled to said analog receiving channels, whereby voice communication between the subscriber locations of the coupled channels is enabled, said switching means including:
• transmultiplexer means for selectively assigning to each analog transmitting channel a corresponding digital transmitting channel for carrying digital voice information corresponding to analog voice information carried by the corresponding analog transmitting channel and for selectively assigning to each analog receiving channel a corresponding digital receiving channel for carrying digital voice information corresponding to analog voice information carried by the corresponding analog receiving channel, said digital channels being in a time division multiplexed (TDM) format;
• said transmultiplexer means including a plurality of analog signal ports for transmitting and receiving electrical signals in a frequency division multiplexed (FDM) format;
• coupling means for coupling each of said analog signal ports to a respective one of said optical fibers, said coupling means converting said FDM electrical signals transmitted by said analog signal ports of said transmultiplexer means into analog optical signals to be transmitted to said telephone subscriber locations via said optical fibers, and said coupling means converting analog optical signals from said telephone subscriber locations received at said coupling means into said FDM electrical signals received at said analog signal ports;
• and
• a digital switch at said central office location for selectively coupling the digital transmitting channels to the digital receiving channels.

A transmultiplexer, comprising:

• at least one TDM interface for receiving and transmitting digital telephone signals in a TDM format from and to a digital signal transmission facility;
• a buffer memory coupled to said at least one TDM interface for temporarily storing said digital telephone signals;
• translation means coupled to said buffer memory for translating said digital telephone signals between said TDM format and an FDM format;
• a plurality of FDM ports for receiving and transmitting analog telephone signals in said FDM format;
• a plurality of A/D conversion means, each coupled between a respective one of said FDM ports and said translation means, said A/D conversion means for converting analog telephone signals into digital telephone signals in said FDM format, and for converting digital telephone signals in said FDM format into analog telephone signals;
• and
• control means coupled to said buffer memory means, said translation means and said A/D conversion means, for transmitting control signals to:
• control respective durations of periods during which said buffer memory stores said digital telephone signals in said TDM format;
• control said translation means to transmit and receive digital signals in said FDM format to and from selected ones of said A/D conversion means;
• and
• control selected ones of said A/D conversion means to receive and transmit digital signals in said FDM format from and to said translation means.