Flexible tributary interface with serial control line

1. A method for transporting Plesiochronous Digital Hierarchy (PDH) tributaries, the method comprising:

accepting an electromagnetic waveform representing a plurality of PDH tributaries;

generating an electromagnetic waveform representing a serial data stream of interleaved PDH tributaries by interleaving the PDH tributaries into a payload of a data frame structure;

generating an electromagnetic waveform representing a serial control stream of signals for recovering the PDH tributaries by loading the control stream into a payload of a control frame structure and generating a control byte for each generated data byte by interleaving control bytes in the control frame structure, aligned with corresponding data bytes in the data frame structure;

generating an electromagnetic waveform clock signal for timing the data and control streams; and,

transmitting the electromagnetic waveforms representing the serial data stream, the serial control stream, and the clock as independent streams to a receiver;

receiving the electromagnetic waveform representing the generated serial data stream;

receiving the electromagnetic waveform representing the generated serial control stream;

receiving the electromagnetic waveform representing the generated clock signal;

in response to the clock signal and serial control stream, disinterleaving the interleaved PDH tributaries as follows:

identifying a frame payload location marker (J0 byte location) in the serial data stream;

identifying a frame payload location marker (J0 byte location) in the serial control stream;

aligning the J0 byte in the serial data stream with the J0 byte from the serial control stream; and,

supplying an electromagnetic waveform representing the plurality of disinterleaved PDH tributaries.

2. The method of claim 1 wherein generating the serial data stream of interleaved PDH tributaries includes transmitting data bytes at a first data rate; and,

wherein generating the serial control stream of signals includes transmitting control bytes at the first data rate.

3. The method of claim 1 wherein disinterleaving the interleaved PDH tributaries includes checking the parity of a data byte in response to decoding information from a corresponding control byte.

4. The method of claim 1 wherein disinterleaving the interleaved PDH tributaries includes identifying the initial information byte in a disinterleaved PDH tributary frame, in response to decoding information from a corresponding control byte.

5. The method of claim 4 wherein disinterleaving the interleaved PDH tributaries includes identifying the location of stuff opportunity and stuff control bytes in the serial data stream, in response to decoding information from the serial control stream.

6. The method of claim 1 wherein disinterleaving the interleaved PDH tributaries in response to the clock signal and serial control stream includes disinterleaving the interleaved PDH tributaries exclusively in response to the clock signal and serial control stream.

7. A system for transporting Plesiochronous Digital Hierarchy (PDH) tributaries, the system comprising:

a transmitter including:

a data framer having an input to accept a plurality of PDH tributaries, the data framer interleaving the PDH tributaries into a payload of a data frame structure and supplying a serial data stream of interleaved PDH tributaries at an output to a receiver;

a control framer having an output to supply a serial control stream of signals to the receiver for recovering the PDH tributaries by loading the control stream into a payload of a control frame structure, generating a control byte for each data byte transmitted by the data framer, and interleaving control bytes into the payload of the control frame structure, aligned with corresponding data bytes in the data frame structure; and,

a clock having an output supplying a clock signal to the receiver for timing the data stream and the control streams;

a receiver including:

a control disinterleaver having an input for receiving the serial control stream, the control disinterleaver identifying a frame payload location marker (J0 byte location) in the serial control stream, and having an output to supply disinterleaved control bytes;

a clock for receiving the clock signal; and,

a data disinterleaver having an input for receiving the serial data stream, the data disinterleaver aligning the serial data stream with the serial control stream by identifying a frame payload location marker (J0 byte location) in the serial data stream, and aligning the J0 byte in the serial data stream with the J0 byte from the serial control stream, and having an output to supply a plurality of PDH tributaries disinterleaved in response to the clock signals and the control bytes.

8. The system of claim 7 wherein the data framer transmits data bytes at a first data rate; and,

wherein the control framer transmits control bytes at the first data rate.

9. The system of claim 7 wherein the control disinterleaver decodes information from a control byte; and,

wherein the data disinterleaver identifies the initial information byte in a disinterleaved PDH tributary frame, in response to receiving the decoded information from the control disinterleaver.