Apparatus and method for providing a transparent interface across a satellite communications link

Claim 2

In a time division communications network having a network clock, a mechanism for characterizing timing between a transmitting and a receiving node, comprising: difference means in said transmitting node, for measuring a difference value between said network clock and a transmitting source clock during consecutive intervals of transmission and transmitting said difference value along with the traffic messages over the communications link to said receiving node; adjustment means at said receiving node, for receiving said difference value and adjusting the receive clock at said receiving node in response thereto; whereby the relative timing between said source clock and said network clock at the transmitting node will have a corresponding relative timing imposed at the receiving node so as to maintain uniform relative timing at said transmitting and receiving nodes during the communications session.

Claim 3

In a time division communications network having a network clock, a mechanism for synchronizing the framing characters in transmitted messages with the framing characters in received messages exchanged between a transmitting and a receiving node, comprising: - difference means in said transmitting node, for measuring a difference value between said network clock and first framing characters received from a transmitting source during consecutive intervals of transmission and transmitting said difference value along with the traffic messages over the communications link to said receiving node; adjustment means at said receiving node, for receiving said difference value and adjusting the receive clock at said receiving node in - response thereto; transmitting means at said receiving node, connected to said adjustment means, for transmitting messages with second framing characters to said transmitting node, said second framing characters being made synchronous with said first framing characters in response to said adjustment means; whereby the relative timing between said first and second framing characters can be adjusted so as to maintain synchronization during the communications session.

Claim 4

The apparatus of claim 3, which further comprises: a multiplexer at said transmitting node to multiplex a plurality of first messages with said first framing characters for transmission to said receiving node; a demultiplexer at said transmitting node to demultiplex a plurality of second messages with said second framing characters from said receiving node; said first and second messages being coincidently synchronized for duplex communication.