Abstract In a two-stage switching network wherein each primary (A) switch has access to each secondary switch over an individual link, the failure of any one link seriously affects accessibility as between incoming and outgoing paths of the network. The present proposal is applicable where said paths are t.d.m. highways as in the digital switching subsystem (D.S.S.), and enables three requirements to be met (1) serial re-routing to avoid effect of an internal faulty link (2) avoidance of normal traffic blockages external to the two-stage network by use of second attempt connection, and (3) arbitrary access to and from digital loss pads providing R.O.M. translation of speech code level. The revised trunking of the two-stage network involves a ''''feed-back link'''' from the outgoing side of each B switch to the incoming side of the corresponding A switch. This enables any failed link to be avoided by 3 passes over the network; one of the passes being over any ''''feed-back link'''' except the two associated with switches of the failed link. Having provided the feed-back links primarily for evasion of faulty direct links, they are additionally used to include said digital loss pads. The t.d.m. channels in any feed-back link are subjected to the loss-pad facility or direct-switching of re-routed connections, as arbitrarily required, by suitable gating. In some circumstances time-sharing of one R.O.M. loss pad between two feed-back links is possible.
Inventors
👤 Alexander Schroder Philip
👤 John Spencer Arnold
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-24 12:22
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04; H04Q11/06
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
120 words
A two-stage full availability telecommunications space switching network particularly adapted for use in a time division multiplex switching system comprising a plurality of primary stage switching matrices adapted to connect groups of receive superhighways to a plurality of interstage links, a plurality of secondary stage switching matrices adapted to connect a number of interstage links to a group of transmit super-highways, each secondary stage switching matrix including one additional outlet and each primary stage switching network including one additional inlet, and a plurality of feed-back paths each interconnecting on a mutually exclusive basis, one additional outlet with one additional inlet, each said feed-back path also including a switchable digital loss pad for allowing selective equalization between incoming and outgoing channels.
Claim 2
Dependent Claim
120 words
A two-stage full availability telecommunications space switching network particularly adapted for use in a time division multiplex switching system comprising a plurality of primary stage switching matrices adapted to connect groups of receive superhighways to a plurality of interstage links, a plurality of secondary stage switching matrices adapted to connect a number of interstage links to a group of transmit super-highways, each secondary stage switching matrix including one additional outlet and each primary stage switching network including one additional inlet, and a plurality of feed-back paths each interconnecting on a mutually exclusive basis, one additional outlet with one additional inlet, each said feed-back path also including a switchable digital loss pad for allowing selective equalization between incoming and outgoing channels.
Claim 3
Dependent Claim
36 words
A two-stage full availability telecommunications space switching network as claimed in claim 1 and in which said digital loss pad comprises a read-only memory in which each location stores the nbd difference value of its address.