Apparatus for conforming the length of a data stream through a transmission line

DETAILED DESCRIPTION A data transmission system is provided in the form of a recirculating loop.
Data is transmitted around the loop in a predetermined format.
Peripheral devices are connected in the transmission system and either transmit into the system for receipt by another peripheral or can receive information sent through the system by the peripheral.
The transmission system must be capable of accommodating a data stream of a definite length and must be capable of maintaining the data stream in synchronism with a reference so the data may be properly interpreted.
A recirculating system should have a means for periodically verifying the data synchronization.
By synchronization, the identity of each data bit location in the data stream can be ascertained and the data appearing in those locations then may be given their proper interpretation.
Further, in a data transmission system gaps should be limited and ideally there should be an absence of gaps between the end of one data bit such as at the end of the data stream and the next following bit such as at the beginning of the recirculated data stream.
This requires that the data be contiguously placed on the line with the first data bit of the recirculated data stream immediately following in that location vacated by the last bit of the data stream.
In a typical installation, portions of the data transmission system will include a line or cable with a varying electrical length.
The electrical length may vary due to temperature or some other extraneous influence or may change due to the addition or removal of peripherals serially in the transmission system.
When the line changes electrical length, then the length of data that can be accommodated by the line changes accordingly.
The phase of the data appearing at the end of the line when the line contracts will appear advanced in phase while the data appearing at the end of the line when the line expands will appear retarded in phase.
Where the length of the data stream is longer than the data line, a supplemental means must be provided for accommodating the excess data and for causing that data to be reinserted into the line in synchronism with the data stream on the line and moving through the system