Call concentrator switching matrix

Claim 2

A call concentrator comprising: a. s subscriber lines; b. t trunk lines, t being smaller than s; and c. relay means for interconnecting said subscriber lines and said trunk lines; said relay means including: i. a group of n line relay boards; ii. a group of n trunk relay boards; and iii. a group of n2 linking buses, each linking bus connecting one of said line relay boards to one of said trunk relay boards; iv. each line relay board being composed of s/n line relay trees each associated with one of said subscriber lines, and each trunk relay board being composed of t/n trunk relay trees, each associated with one of said trunk lines, said relay trees being arranged to interconnect said linking buses with said subscriber lines and trunk lines.

Claim 3

The device of claim 1, in which n 2 m - 1, m being a positive integer, and in which each said relay tree consists of m relays, said relays being individually switchable to provide each relay tree with 2m combinations of relay positions, one of said combinations being a neutral condition in which said relay tree establishes a connection indicative of an idle or service request on its subscriber line, the n other combinations being active conditions in which the relay tree connects its subscriber or trunk line with one of said linking buses for talking purposes.

Claim 4

The device of claim 2, in which m 3, n 7, s 112, and t 21.

Claim 5

The device of claim 2, further comprising a set of terminals, one terminal being connected to each subscriber line through the line relay tree associated with that line when the line relay tree is in its neutral condition, scanning means cyclically sequentially connectable to said terminals, a voltage source, and means connecting said voltage source to each said terminal through the contacts of the relay tree associated therewith which are closed in the neutral condition of said relay tree, and through the line associated therewith so as to change the voltage at said terminal when said relay tree switches from said neutral condition to an active condition or when the subscriber set associated therewith goes off-hook while said line relay tree is in its neutral condition.

Claim 6

The device of claim 2, in which said relay boards are plug-in printed circuit boards, and in which said lines, trunks, and linking buses are wired to connectors into which said boards are plugged in such a manner that said concentrator may be operated in a partially equipped condition to serve a smaller number of lines than its full-capacity complement.

Claim 7

The device of claim 2, in which said relays are of the magnetic latching type.

Claim 8

A call concentrator comrising: a. s subscriber lines; b. t trunk lines, t being smaller than s; and c. relay means for interconnecting said subscriber lines and said trunk lines; said relay means including: i. a group of n line relay boards; ii. a group of n trunk relay boards; and iii. a group of n2 linking buses, each linking bus connecting one of said line relay boards to one of said trunk relay boards; iv. each line relay board being composed of s/n line relay trees each associated with one of said subscriber lines, and each trunk relay board being composed of t/n trunk relay trees, each associated with one of Said trunk lines, said relay trees being arranged to interconnect said linking buses with said subscriber lines and trunk lines; and v. said relay trees consisting of m relays each arranged to switch both the tip and the ring lead of the line associated therewith between 2m position combinations, the first of said relays having 20 tip contacts and 2m 1 ring contacts, the second relay having 21 tip contacts and 2m 1 ring contacts, and so forth to the last relay having 2m 1 tip contacts and 2* ring contacts.

Claim 9

A call concentrator comrising: a. s subscriber lines; b. t trunk lines, t being smaller than s; and c. relay means for interconnecting said subscriber lines and said trunk lines; said relay means including: i. a group of n line relay boards; ii. a group of n trunk relay boards; and iii. a group of n2 linking buses, each linking bus connecting one of said line relay boards to one of said trunk relay boards; iv. each line relay board being composed of s/n line relay trees each associated with one of said subscriber lines, and each trunk relay board being composed of t/n trunk relay trees, each associated with one of Said trunk lines, said relay trees being arranged to interconnect said linking buses with said subscriber lines and trunk lines; and v. said relay trees consisting of m relays each arranged to switch both the tip and the ring lead of the line associated therewith between 2m position combinations, the first of said relays having 20 tip contacts and 2m 1 ring contacts, the second relay having 21 tip contacts and 2m 1 ring contacts, and so forth to the last relay having 2m 1 tip contacts and 2* ring contacts.

Claim 12

A call concentrator comrising: a. s subscriber lines; b. t trunk lines, t being smaller than s; c. relay means for interconnecting said subscriber lines and said trunk lines; said relay means including: i. a group of n line relay boards; ii. a group of n trunk relay boards; and iii. a group of n2 linking buses, each linking bus connecting one of said line relay boards to one of said trunk relay boards; iv. each line relay board being composed of s/n line relay trees each associated with one of said subscriber lines, and each trunk relay board being composed of t/n trunk relay trees, each associated with one of said trunk lines, said relay trees being arranged to interconnect said linking buses with said subscriber lines and trunk lines; v. each said relay tree consisting of m relays, m being a positive integer with n 2m - 1, said relays being individually switchable to provide each relay tree with 2m combinations of relay positions, one of said combinatins being a neutral condition in which said relay tree establishes a connection indicative of an idle or service request on its subscriber line, the n other combinations being active conditions in which the relay tree connects its subscriber or trunk line with one of said linking buses for talking purposes; d. a set of terminals, each terminal being connected to one of said subscriber lines through one of said line relay trees when that line relay tree is in its neutral condition; e. scanning means cyclically sequentially connectable to said terminals; f. a voltage source; and g. means connecting said voltage source to each said terminal through the contacts of the relay tree associated therewith which are closed in the neutral condition of said relay tree, and through the line associated therewith so as to change the voltage at said terminal when said relay tree switches from said neutral condition to an active condition or the subscriber set associated therewith is off-hook when said line relay tree is in its neutral condition, h. said voltage source being connected through the on-hook resistance of the subscriber set in series with a load resistor, said on-hook resistance and load resistor forming a voltage divider, and said idle terminal being connected to a point between said on-hook resistance and said load resistor.

Claim 13

A call concentrator comrising: a. s subscriber lines; b. t trunk lines, t being smaller than s; c. relay means for interconnecting said subscriber lines and said trunk lines; said relay means including: i. a group of n line relay boards; ii. a group of n trunk relay boards; and iii. a group of n2 linking buses, each linking bus connecting one of said line relay boards to one of said trunk relay boards; iv. each line relay board being composed of s/n line relay trees each associated with one of said subscriber lines, and each trunk relay board being composed of t/n trunk relay trees, each associated with one of said trunk lines, said relay trees being arranged to interconnect said linking buses with said subscriber lines and trunk lines; v. each said relay tree consisting of m relays, m being a positive integer with n 2m - 1, said relays being individually switchable to provide each relay tree with 2m combinations of relay positions, one of said combinatins being a neutral condition in which said relay tree establishes a connection indicative of an idle or service request on its subscriber line, the n other combinations being active conditions in which the relay tree connects its subscriber or trunk line with one of said linking buses for talking purposes; d. a set of terminals, each terminal being connected to one of said subscriber lines through one of said line relay trees when that line relay tree is in its neutral condition; e. scanning means cyclically sequentially connectable to said terminals; f. a voltage source; and g. means connecting said voltage source to each said terminal through the contacts of the relay tree associated therewith which are closed in the neutral condition of said relay tree, and through the line associated therewith so as to change the voltage at said terminal when said relay tree switches from said neutral condition to an active condition or the subscriber set associated therewith is off-hook when said line relay tree is in its neutral condition, h. said voltage source being connected through the on-hook resistance of the subscriber set in series with a load resistor, said on-hook resistance and load resistor forming a voltage divider, and said idle terminal being connected to a point between said on-hook resistance and said load resistor.