Automatic line transfer system and method for a communications system

Claim 2

In a communications system having a plurality of working lines each of said working lines including a plurality of spans having ends beginning and terminating at offices remote from a command office, an automatic line transfer system for automatically switching the ends of a working line corresponding to both ends of a failed span of one of said plurality of working lines to a protection line without service interruption said transfer system comprising: means for sensing a failed span of a working line; means responsive to said sensing means for switching said ends of said working line corresponding to both ends of said failed span to a corresponding span of said protection line whereby said failed span is looped around; and means for cross-connection said failed span to the preceding span of said protection line to connect said failed span to said command office.

Claim 3

A system as in claim 1 together with means for looping said failed line at an end remote from said command office.

Claim 4

A system as in claim 1 together with system fault indicating means coupled to protection line in said command office for indicating said line failure.

Claim 5

A system as in claim 1 together with violation monitor and remover (VMR) means connected in both said working lines and protection line for preventing propogation of errors from span to span and means responsive to an interrogation code for disabling the VMR means associated with said failed line.

Claim 6

A system as in claim 1 including code generator means connected to said protection line for generating a keep alive code and means connected to said protection line for detecting the absence of said keep alive code to thereby indicate a system fault.

Claim 7

A system as in claim 1 where said working lines are in pairs with each line of a pair serving as a communication path in one direction together with means responsive to said sensing means sensing failure on one direction of a line pair for generating an error code in the other direction of said line pair.

Claim 8

A system as in claim 1 together with means responsive to said sensing means indicating a failure is no longer present on a working line for automatically resetting said switching means to eliminate said protection line loop around said working line.

Claim 9

A system as in claim 7 where said resetting means includes timing means for timing said no failure indication a predetermined time before resetting.

Claim 10

A system as in claim 1 together with, means responsive to said sensing means indicating a failure is no longer present on a working line for resetting said line, manually actuated reset code generating means coupled to said protection line in said command office, means in each of said remote offices for sensing said reset code and responsive to said reset code for enabling said resetting means.

Claim 11

A system as in claim 1 together with an additional protection line and priority control means associated with each of said protection lines for assigning a predetermined one of said protection lines a first priority for transfer of a failed line.

Claim 12

A system as in claim 1 where said offices include a divergent office having a stem and legs and where a single protection line in said stem is looped around said legs.

Claim 13

In a communications system having a plurality of working lines each of said working lines including a plurality of spans having ends beginning and terminating at offices remote from a command office, an automatic line transfer system for automatically switching the ends of a working line corresponding to both ends of a failed span of one of said plurality of working lines to a protection line without service interruption, said transfer system comprising: means for sensing a failed span of a working line; means included in said protection line at said command office for indicating a system fault; means responsive to said sensing means for switching said ends of said working line corresponding to both ends of said failed span to a corresPonding span of said protection line whereby said failed span is looped around; and means for connecting said failed span to said system fault indicating means of said protection line at said command office.

Claim 14

In a communications system having a plurality of working lines each of said working lines including a plurality of spans having ends beginning and terminating at offices remote from a command office, an automatic line transfer system for automatically switching the ends of a working line corresponding to both ends of a failed span of one of said plurality of working lines to a protection line without service interruption, said transfer system comprising: means for sensing a failed span of a working line; means included in said protection line at said command office for indicating a system fault; means responsive to said sensing means for switching said ends of said working line corresponding to both ends of said failed span to a corresPonding span of said protection line whereby said failed span is looped around; and means for connecting said failed span to said system fault indicating means of said protection line at said command office.

Claim 17

A method as in claim 13 including the step of interrogating said failed line from said command office via said protection line to determine the location of said failed line.