Apparatus for, and method of, packing and unpacking information in transmission lines

In combination for coding information in successive symbols each having a plurality of binary bits to obtain a reduced number of binary bits in character frames defined by a particular number of successive symbols to obtain a transmission of such character frames through a transmission line where each symbol provides user information or control information and where an identification one of the bits in each symbol identifies whether the information in the symbol is user information or control information,

• first means for providing the binary bits in the successive symbols for conversion to the character frame,
• second means for separating the binary bits in each symbol in the character frame into first and second portions respectively having first and second particular numbers of binary bits, the second portion of each symbol including the identification bit,
• latch means,
• third means for positioning the first particular numbers of binary bits in the different symbols for the character frame in adjacent relationship in the latch means,
• fourth means for converting the second particular number of binary bits in the different symbols in the character frame into a reduced number of binary bits indicating decimal value where each decimal integer in the decimal value represents the decimal significance of the second portion of an individual one of the symbols in the character frame,
• fifth means for introducing the reduced number of binary bits indicating the decimal value in each character frame into the latch means in adjacent relationship to the first particular numbers of binary bits in the character frame.

In combination for providing for the transmission of symbols in a transmission line where successive groups of symbols are provided in successive character frames,

• first means for providing a first plurality of channels first ones of which provide symbols periodically at individual rates and second ones of which provide signals aperiodically,
• a line,
• second means for introducing symbols to the line from the different channels on a priority basis primarily in accordance with the rates of occurrence of the periodic symbols in the first channels and secondarily in accordance with the aperiodicity of the symbols in the second channels,
• latch means,
• third means for introducing first portions of the successive symbols in each character frame to the latch means,
• second portions of the symbols in each character frame having a particular number of binary bits representing a decimal number of an individual decimal significance,
• fourth means responsive to the second portions of the symbols in each character frame for reducing the composite number of the binary bits in such second portions to a binary value representative of the decimal value defined by giving a different decimal significance to the decimal numbers of the individual binary significance, and
• fifth means for releasing the binary indications in the latch means from the latch means for transmission through the line.

In combination at a receiver in a transmission system for converting a character frame into a group of symbols each having a particular number of binary bits where the character frame has a plurality of binary bits less than the total number of binary bits in the symbols in the group and where the last portion of each symbol in the group is represented in the character frame by binary indications of the decimal value of such last portion and where the last portion for each symbol in the group has an individual decimal significance and where the binary indications for a first portion of each symbol in the group are provided in the character frame without change and where the symbols in each group have been converted into the character frame at a transmitter in the transmission system,

• first means at the receiver for receiving the binary indications in the character frame,
• second means for converting the binary indications in the character frame of the decimal values of the last portions of the symbols in the group into a plurality of binary indications for the last portion of each symbol in the group where the plurality of the binary indications for the last portion of each symbol in the group have a decimal value at the receiver corresponding to the decimal value of the last portion of such symbol at the transmitter and have an individual decimal significance at the receiver corresponding to the individual decimal significance of the last portion of such symbol at the transmitter,
• third means for recovering the binary indications in the first portion of each symbol in the group from the character frame, and
• fourth means for restoring the converted binary indications in the last portion of the symbols in the group and the binary indications in the first portions of such symbols in the group to recover the different symbols in the group.

In combination at a receiver in a transmission system for separating symbols in a sequence of time slots into a plurality of channels where the transmitter in the transmission system combines the symbols from different channels to form the sequence of time slots and where the channels at the transmitter with periodic symbols have a priority in the time slots over the channels with the aperiodic symbols and where the channels at the transmitter with periodic symbols have priorities relative to one another in accordance with the periodicity of the symbols,

• first means at the receiver for receiving the sequence of symbols in the time slots,
• second means at the receiver for providing a separation of the periodic symbols from the aperiodic symbols,
• third means at the receiver for providing a separation of the periodic symbols by the second means into a plurality of channels in accordance with the periodicity of the symbols,
• fourth means at the receiver for providing an additional channel different from the channels in the plurality for receiving the aperiodic symbols
• fifth means for introducing the periodic signals into the individual channels in the plurality in accordance with their periodicity, and
• sixth means for introducing the aperiodic signals into the additional channel.