Use of robbed framing bits to provide secondary pots channel over extended range ISDN communications network
AssigneeAdtran, Inc.
InventorsMichael Scott Sansom, Timothy D. Rochell
Life of this patent
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Abstract
The currently defined industry standard framing structure for 2B1Q ISDN signaling, at 160 kilobaud, provides 128 kbps for a customer (B1, B2) data channel, and 16 kbps for a data (D) channel. Of the remaining 16 kbps non payload bandwidth, 4 kbps are used for overhead maintenance data. Eight kbps of the remaining 12 kbps of non payload bandwidth, that customarily transport a repeated framing pattern, are usurped for the transport of an auxiliary compressed (from 64 KHz to 8 KHz) digitized voice POTS channel, that is sufficient to transport toll quality voice. The remaining framing pattern bandwidth is adequate prevent an unacceptable reduction in bit error rate.
Claims17
A method of transporting a secondary voice channel by way of an integrated services digital network (ISDN) communication link having a transport bandwidth that includes a bearer channel bandwidth, a data channel bandwidth, maintenance channel bandwidth and a framing pattern bandwidth, comprising the steps of:
- (a) providing a digitized secondary voice channel that is compressed to a bandwidth less than said framing pattern bandwidth;
- and
- (b) replacing a portion of framing information contained in said framing pattern bandwidth with said digitized secondary voice channel provided in step (a).
A method of transporting a secondary voice channel by way of an integrated services digital network (ISDN) communication system having a framing structure that includes a bearer channel bandwidth, a data channel bandwidth and a repeated framing pattern bandwidth, comprising the steps of:
- (a) providing a digitized secondary voice channel that is compressed to a bandwidth less than said repeated framing pattern bandwidth;
- and
- (b) replacing selected framing bits of selected repeated framing patterns that make up said repeated framing pattern bandwidth with bits of said digitized secondary voice channel.
An arrangement for transporting a secondary voice channel by way of an integrated services digital network (ISDN) communication link having a transport bandwidth that includes a bearer channel bandwidth, a data channel bandwidth, a maintenance channel bandwidth and a framing pattern bandwidth, said arrangement comprising:
- a framing multiplexer that is operative to assemble contents of said bearer channel, said data channel, said maintenance channel and said framing pattern for transport over said ISDN communication link;
- and
- a framing controller, which is operative to cause said framing multiplexer to replace a portion of framing information contained in said framing pattern with a secondary voice channel.
Dependencies are inferred from the claim text.