Optical fiber connector buildout system

• US 5,067,783 A
• Filed: 10/16/1990
• Issued: 11/26/1991
• Est. Priority Date: 10/16/1990
• Status: Expired due to Term

• Current Assignee: Fitel USA Corporation (Furukawa Electric Company Limited)
• Original Assignee: AT&T, Inc.
• Inventors: Lampert, Norman R.
• Primary Examiner(s): Gonzalez, Frank
• Assistant Examiner(s): NGO, HUNG NHAT
• Application Number:
  US07/598,497
• Time in Patent Office: 406 Days
• Field of Search: 350/96.2, 350/96.21, 350/96.22
• US Class Current: 385/60
• CPC Class Codes: G02B 6/264 with optical elements between opposed fibre ends which perform a function other than beam splitting having lens focusing means G02B6/32; utilising prism or grating G02B6/34
• CPC Class Codes: G02B 6/3821 with axial spring biasing or loading means G02B6/3847 takes precedence
• CPC Class Codes: G02B 6/3831 comprising a keying element on the plug or adapter, e.g. to forbid wrong connection keying element on the ferrule G02B6/3851; keying element for electrical coupling H01R13/64
• CPC Class Codes: G02B 6/3854 Ferrules characterised by materials
• CPC Class Codes: G02B 6/3877 Split sleeves
• CPC Class Codes: G02B 6/3891 Bayonet type
• CPC Class Codes: G02B 6/3897 Connectors fixed to housings, casing, frames or circuit boards G02B6/44528 takes precedence

Abstract

A connector system (20) for interconnection of optical fiber ferrule connectors in optical wiring panels includes an array of buildout blocks (70,70) which are mounted in a panel (60). Each buildout block includes a tubular portion (76) having a keyway and provisions for receiving a buildout (100,150) which upon suitable alignment and rotation relative to the buildout block is caused to be secured to the buildout block. The buildout (100) which is adapted to receive an ST® connector includes a first tubular portion (103) in which is disposed a sleeve (107) for receiving a plug (40) of a plug assembly (22) of the connector system in one end thereof which has been inserted into the tubular portion of the buildout block with a key (43) thereof received in the keyway (78) of the tubular portion of the buildout block. Also, the sleeve is capable of having an attenuator element (140) mounted therein. In another end of the buildout, a plug (40,182) of another plug assembly is secured to a second tubular portion (102) of the buildout to allow an optical connection between fibers terminated by the plugs to be made. The plug which is secured to the second tubular portion of the buildout (150) may be that of an FC connector. Advantageously, the buildouts which represent a substantial portion of the connection need not be installed until service is required. Further, the system is such that a choice of ferrule connectors is permitted with the same buildout block. Buildouts which have attenuator elements mounted therein and those which do not are interchangeable with each other without the need for special tools.

Claims

1. An optical fiber connector system, which comprises:

two plug assemblies each of which includes a plug which terminates an optical fiber and at least one of which includes a key;

a buildout block which is adapted to be mounted in an opening in a panel, said buildout block including a tubular portion having a longitudinally extending keyway formed in a wall thereof and extending from a flanged end which includes track and latching means, said buildout block including first and second cavities which communicate with each other through an opening in an internally disposed wall with said first cavity opening to the flanged end of said buildout block and said second cavity opening to an opposite end of said buildout block;

a buildout which includes first and second coaxially aligned tubular portions which extend in opposite directions from a flanged portion which includes means adapted to cooperate with said track and latching means of said buildout block to secure said buildout to said buildout block upon suitable relative motion which is caused to occur between said buildout and said buildout block, said first tubular portion adapted to be received in said first cavity of said buildout block and said second tubular portion including means for causing one of said plugs which is inserted into said second tubular portion to become secured therewithin; and

a sleeve which is disposed in said first tubular portion of said buildout and which is adapted to receive in one end an end portion of one of said plugs which becomes disposed in said tubular portion of said buildout block and in an opposite end thereof the other one of said plugs which becomes disposed in said second tubular portion of said buildout to cause an optical connection to be made between the optical fibers terminated by said plugs, said sleeve including a longitudinally extending slot in a wall thereof and said key of said at least one plug assembly being received in said keyway of said tubular portion of said buildout block when said plug of said at least one plug assembly is received in said tubular portion of said buildout block.

2. The connector system of claim 1, wherein said buildout and said buildout block are such as to receive and cause a connection between first and second plug assemblies which are different from each other, wherein said second tubular portion of said buildout is threaded externally and is disposed concentrically about and spaced from a boss which is adapted to receive a plug of said second plug assembly and wherein said longitudinally extending keyway of said tubular portion of said buildout block is adapted receive a key which extends radially from a connector body in which said plug of said first plug assembly is mounted, said tubular portion of said buildout block including two diametrically opposed pins extending therefrom to be received in latching slots of a cap in which the connector body of said first plug assembly is mounted.

3. The optical fiber connector system of claim 1, wherein a second one of said tubular portions of said buildout includes an outer portion which is threaded externally and an inner boss which is disposed concentrically within and spaced from said outer portion and wherein the tubular portion of said buildout block includes a longitudinally extending keyway therein and two diametrically opposed latching pins projecting from an outer surface thereof, said two plug assemblies including first and second plug assemblies,

said second one of said plug assemblies including a plug extending from a connector body which is adapted to become disposed about said boss of said second tubular portion of said buildout when said plug of said second plug assembly is received in said second tubular portion of said buildout and in said sleeve and further including a cap which is slideably moveable and which is internally threaded to be turned threadably over said outer portion of said second tubular portion of said buildout when said plug of said second plug assembly is received in said sleeve;

and

said first one of said plug assemblies including a connector body from which a plug extends, said connector body of said first plug assembly having a key projecting therefrom to be received in said keyway of said buildout block when said plug of said first plug assembly is received in said tubular portion of said buildout block and in said sleeve, said first one of said plug assemblies also including a cap which is disposed concentrically about at least a portion of said connector body and which includes two camming slots and associated latching slots so that as said plug of said first plug assembly is inserted into said sleeve and said key is received in said keyway of said buildout block, each of said pins of said buildout block is caused to be moved along a camming slot and become disposed in the latching slot associated therewith to hold said cap of said first plug assembly secured to said tubular portion of said buildout block.

4. The optical fiber connector system of claim 3, wherein said first plug assembly includes a compression spring disposed about said connector body thereof and said second plug assembly includes resilient means for biasing the plug thereof outwardly of said second plug assembly.

5. The optical fiber connector system of claim 1, which comprises

a first plug assembly which includes a cylindrical plug;

a second plug assembly which includes a cylindrical plug, each plug of each said plug assembly having a passageway therethrough and being adapted to terminate an optical fiber disposed in the passageway and a cap which encloses a portion of said plug, each of said plug assemblies including means for causing said plug thereof to be biased outwardly in a direction from a fiber entrance end toward an opposite end thereof;

wherein said track means of said buildout block includes circular track means; and

said buildout including tab means cooperating with said circular track means and latching means of said buildout block to secure said buildout to said buildout block upon suitable relative rotary motion which is caused to occur between said buildout and said buildout block;

said first tubular portion of said buildout adapted to be received in said first cavity of said buildout block and said second tubular portion including a longitudinal keyway which upon securement of said buildout to said buildout block is aligned longitudinally with said keyway in said tubular portion of said buildout block, the cap of said second plug assembly being adapted to be secured to an end portion of said second tubular portion of said buildout and the cap of said first plug assembly being adapted to be secured to an end portion of the tubular portion of said buildout block.

6. The connector system of claim 5, wherein said tab means of said buildout includes a tab having an end which is deflectable generally radially inwardly toward a longitudinal axis of said buildout, the tab adapted to be received between an overhang of said track means and a surface of said flanged end of said buildout block so that when said first tubular portion of said buildout is inserted into said buildout block and turned, said tab snap-locks into a secured position.

7. The connector system of claim 5, wherein said flanged portion of said buildout includes a locking tab having an end which is deflectable generally radially inwardly toward a longitudinal axis of said buildout and a guide tab, each said tab adapted to be received between an overhang of said circular track means and a surface of said flanged end of said buildout block which is spaced from said overhang as relative rotary motion is caused to occur between said buildout block and said buildout, said locking tab including a free end which is adapted to snap-lock into a secured position as a portion of each said tab is received between said overhang and said surface.

8. The connector system of claim 5, wherein each of said plug assemblies includes a cap having an annular inwardly projecting lip through which a connector body in which is disposed an end portion of the plug of said each plug assembly extends, said connector body having an enlarged end portion in which is disposed said end portion of said plug, each said plug assembly also including a retaining clip which is disposed about said connector body adjacent to an inner side of said lip and a compression spring disposed about said connector body and engaging an outer side of said lip and an inner side of said enlarged portion of said connector body to urge said connector body and plug outwardly with said retaining clip holding said plug in said cap, said connector body also including a key which projects radially from and is attached to said enlarged portion thereof;

the key of said connector body of said first plug assembly being adapted to become disposed in said keyway of said buildout block as said plug of said first plug assembly is caused to become disposed in said tubular portion of said buildout block, and said key of said connector body of said second plug assembly being adapted to become disposed in said keyway of said second tubular portion of said buildout.

9. The connector system of claim 8, wherein said tubular portion of said buildout block and said second tubular portion of said buildout each includes two diametrically opposed pins which extend radially from said buildout block and from said buildout and which are adapted to be received in latching slots which are provided in said caps in which said connector bodies are mounted to secure said plug assemblies to said buildout block and to said buildout and to prevent inadvertent rotary motion between said tubular portion of said buildout block and said cap of said first plug assembly and rotary motion between said tubular portion of said buildout and said cap of said second plug assembly which is secured thereto.

10. The connector of claim 9 wherein each said cap includes two diametrically opposed camming slots each of which extends from a free end of said cap inwardly helically about said cap, each of said camming slots communicating with an associated latching slot which extends from an inner end of the associated camming slot outwardly in a direction parallel to a longitudinal axis of said plug, each said cap also being provided with diametrically opposed entrances, each said entrance at a free end of said cap communicating with an outer end of an associated camming slot, said second tubular end portion of said buildout including a longitudinally extending keyway which extends from an entrance end of said second tubular end portion and a pair of diametrically opposed latching pins projecting outwardly from said second tubular portion, said pins and said keyway being such that when a cap of a plug assembly is aligned with said buildout such that the key of the plug thereof is aligned with said keyway in said second tubular end of said housing, said pins of the buildout are aligned with said camming slots of said cap and adapted to be moved along said entrances into said camming slots and into said latching slots to allow said plug assembly to be secured to said buildout.

11. The connector system of claim 5, wherein said tubular portion of said buildout block includes a threaded portion which is adapted to extend partially through an opening in a panel and to receive a threaded fastener to secure said buildout block to said panel.

12. The connector system of claim 5, wherein said buildout and said buildout block are such as to receive identical plug assemblies at ends thereof to facilitate a connection between said identical plug assemblies.

13. The connector system of claim 1, which also includes

an attenuating element comprising a plate-like portion being made of a material having an index of refraction substantially equal to that of glass, and a rail including a depending portion from which said plate-like portion is supported, said depending portion received in said slot of said sleeve with said plate-like portion disposed in said sleeve and with a portion of said rail disposed adjacent to an outer surface of said sleeve, said attenuating element being capable of being moved longitudinally slideably along said sleeve as each said plug is inserted into said sleeve and said element being engaged by each said plug when said plugs are seated in said sleeve.

14. The optical fiber connecting system of claim 13, which includes first and second plug assemblies and wherein said sleeve is disposed in said first tubular portion of said buildout, the second tubular portion of said buildout including an outer portion which is threaded externally and an inner boss which is disposed concentrically within and spaced from said outer portion and wherein the opposed tubular end portion of said buildout block includes a tubular portion having a longitudinally extending keyway therein and two diametrically opposed latching pins projecting from an outer surface thereof;

said second one of said plug assemblies including a plug extending from a connector body which is adapted to become disposed about said boss of said second end portion of said buildout when said plug of said second plug assembly is received in said sleeve and further including a cap which is slideably moveable and which is internally threaded to be turned threadably over said outer portion of said second tubular portion of said buildout when said plug of said second plug assembly is received in said sleeve; and

said first one of said plug assemblies including a connector body from which a plug extends, said connector body of said first plug assembly having a key projecting therefrom to be received in said keyway of said tubular portion of said buildout block when said plug of said first plug assembly is received in said sleeve, said first one of said plug assemblies also including a cap which is disposed concentrically about at least a portion of said connector body and which includes two camming slots and associated latching slots so that as said plug of said first plug assembly is inserted into said sleeve and said key is received in said keyway of said buildout block, each of said pins of said buildout block is caused to be moved along a camming slot and become disposed in the latching slot associated therewith to hold said cap of said first plug assembly secured to said buildout block.

15. The connector system of claim 14, wherein said first plug assembly includes a compression spring disposed about said connector body thereof and said second plug assembly includes resilient means for biasing said first plug thereof outwardly of said second plug assembly.

16. A buildout system for connecting optical fibers terminated by plugs of first and second optical fiber plug assemblies, said buildout system including:

a buildout block which is adapted to be mounted in an opening in a panel and adapted to have a plug assembly connected thereto, said buildout block including a tubular portion having a longitudinally extending keyway formed in a wall thereof and extending from a flanged end which includes track and latching means, said buildout block including first and second cavities which communicate with each other through an opening in an internally disposed wall with said first cavity opening to the flanged end of said buildout block and said second cavity opening to an opposite end of said buildout block;

a buildout which includes first and second coaxially aligned tubular portions which extend in opposite directions from a flanged portion which includes securing means adapted to cooperate with said track and latching means of said buildout block to secure said buildout to said buildout block upon suitable relative rotary motion which is caused to occur between said buildout and said buildout block, said first tubular portion adapted to be received in said first cavity of said buildout block and said second tubular portion including securing means for causing a plug assembly which is assembled thereto to be secured against unintentional rotary motion; and

a sleeve which is disposed in said first tubular portion of said buildout and which is adapted to receive in one end thereof an end portion of a plug of a plug assembly which becomes disposed in said tubular portion of said buildout block and in an opposite end thereof another plug which becomes disposed in said second tubular portion of said buildout to cause an optical connection to be made between optical fibers terminated by the plugs, said sleeve including a longitudinally extending slot in a wall thereof and said longitudinal keyway of said buildout block and said securing means of said buildout cooperating with portions of said plug assemblies assembled thereto to prevent unintended rotary motion of said plug assemblies.

17. The buildout system of claim 16, wherein said second tubular portion of said buildout includes a keyway extending longitudinally therealong.

18. The buildout system of claim 17, wherein each plug assembly includes a plug adapted to be inserted into an end of said sleeve and disposed within a connector body which is mounted within a cap, the connector body being biased outwardly from the cap, the connector body including a key, the key of the connector body in which is mounted the plug of a first plug assembly being adapted to become disposed in said keyway of said buildout block as the plug of the first plug assembly is caused to become disposed in said tubular portion of said buildout block, and the key of the connector body in which the plug of a second plug assembly is mounted being adapted to become disposed in said keyway of said second tubular portion of said buildout.

19. The buildout system of claim 18, wherein said tubular portion of said buildout block and said second tubular portion of said buildout each includes two diametrically opposed pins which extend radially from said buildout block and from said buildout and which are adapted to be received in latching slots which are provided in caps in which the connector bodies of the plug assemblies are mounted to secure the plug assemblies to said buildout block and to said buildout.

20. The buildout system of claim 16, wherein said buildout includes at one end thereof a tab having an end which is deflectable generally radially inwardly toward a longitudinal axis of said buildout, the tab adapted to be received between an overhang and a surface of said flanged end of said buildout block so that when said buildout is inserted into said buildout block and turned, said tab snap-locks into a secured position.

21. The buildout system of claim 16, wherein said flanged portion of said buildout includes a locking tab having an end which is deflectable generally radially inwardly toward a longitudinal axis of said buildout and a guide tab, each said tab adapted to be received between an overhang and a surface of said flanged end of said buildout block which is spaced from said overhang as relative rotary motion is caused to occur between said buildout block and said buildout and said locking tab including a free end which is adapted to snap-lock into a secured position as each said tab is received between said overhang and said surface.

22. The buildout system of claim 16, wherein said tubular portion of said buildout block includes a threaded portion which is adapted to extend partially through an opening in a panel and to receive a threaded fastener to secure said buildout block to said panel.

23. The buildout system of claim 16, wherein said buildout and said buildout block are such as each to receive substantially identical plug assemblies at ends thereof to facilitate a connection between said substantially identical plug assemblies.

24. The buildout system of claim 16, which also includes

an attenuating element comprising a plate-like portion being made of a material having an index of refraction substantially equal to that of glass, and a rail including a depending portion from which said plate-like portion is supported, said depending portion received in said slot of said sleeve with said plate-like portion disposed in said sleeve and with a portion of said rail disposed adjacent to an outer surface of said sleeve, said attenuating element being capable of being moved longitudinally along said sleeve as each plug is inserted into said sleeve and said element being engaged by each plug when plugs are seated in said sleeve.

25. The buildout system of claim 16, which is adapted to connect optical fibers terminated by plugs of first and second plug assemblies and wherein said sleeve is disposed in said first tubular portion of said buildout, said second one of said tubular portions including an outer portion which is threaded externally and an inner boss which is disposed concentrically within and spaced from said outer portion and wherein the tubular portion of said buildout block includes two diametrically opposed latching pins projecting from an outer surface thereof,

a second one of the plug assemblies including a plug extending from a connector body which is adapted to become disposed about said boss of said second tubular portion of said buildout when a plug is received in said sleeve and further including a cap which is slideably moveable and which is internally threaded to be turned threadably over said outer portion of said second tubular portion of said buildout when a plug of the second plug assembly is received in said sleeve;

and

a first one of said plug assemblies including a connector body from which a plug extends, the connector body of the second plug assembly having a key projecting therefrom to be received in said keyway of said tubular portion of said buildout block when the plug of the first plug assembly is received in said sleeve, the first one of said plug assemblies also including a cap which is disposed concentrically about at least a portion of the connector body and which includes two camming slots and associated latching slots so that when the plug of the first plug assembly is inserted into said sleeve and said key thereof is received in said keyway of said tubular portion of said buildout block, each of said pins of said buildout block is caused to be moved along a camming slot and become disposed in the latching slot associated therewith to hold said cap of said first plug assembly assembled to said buildout block.

26. The buildout system of claim 25 wherein the first plug assembly includes a compression spring disposed about said connector body thereof and the second plug assembly includes resilient means for biasing the plug thereof outwardly of said second plug assembly.

27. An optical fiber connection, which includes:

first and second plug assemblies each of which includes a plug having a passageway therethrough, a connector body in which said plug is mounted and a cap in which said connector body is mounted, each said plug of each said assembly terminating an optical fiber which is received in said passageway of said plug and at least one of said plug assemblies including a key;

a buildout block which is mounted in an opening in a panel, said buildout block including a tubular portion having a longitudinally extending keyway formed in a wall thereof and extending from a flanged end which includes track and latching means, said buildout block including first and second cavities which communicate with each other through an opening in an internally disposed wall with said first cavity opening to the flanged end of said buildout block and said second cavity opening to an opposite end of said buildout block;

a buildout which includes first and second coaxially aligned tubular portions which extend in opposite directions from a flanged portion which includes means cooperating with said track and latching means of said buildout block to secure said buildout to said buildout block, said first tubular portion being received in said first cavity of said buildout block and said second tubular portion including means for causing one of said plugs which is disposed in said second tubular portion to secured therewithin; and

a sleeve which is disposed in said first tubular portion of said buildout and in one end of which is received an end portion of one of said plugs which is disposed in said tubular portion of said buildout block and in an opposite end thereof is received the plug of the other one of said plug assemblies which is disposed in said second tubular portion of said buildout to cause an optical connection to be made between the optical fibers terminated by the plugs, said sleeve including a longitudinally extending slot in a wall thereof and said key of said at least one plug assembly being received in said keyway of said tubular portion of said buildout block.

28. The connection of claim 27, wherein each of said plug assemblies includes means for causing said plug thereof to be biased outwardly in a direction from a fiber entrance end toward an opposite end thereof and wherein said track means of said buildout block includes circular track means;

and

said buildout including means which cooperated with said circular track and latching means of said buildout block to secure said buildout to said buildout block upon suitable relative rotary motion which was caused to occur between said buildout and said buildout block, one said cap being secured to an end portion of said second tubular portion of said buildout and the other cap being secured to an end portion of the tubular portion of said buildout block;

said first tubular portion of said buildout received in said first cavity of said buildout block and said second tubular portion of said buildout including a longitudinal keyway which is aligned longitudinally with said keyway in said tubular portion of said buildout block.

29. The connection of claim 28, wherein said flanged portion of said buildout includes a tab having an end which is deflectable generally radially inwardly toward a longitudinal axis of said buildout, said tab being received between an overhang of said circular track means and a surface of said flanged end of said buildout which is spaced from said overhang as rotary motion was caused to occur between said buildout block and said buildout, said tab including a free end which is snap-locked into a secured position as a portion of said tab was received between said overhang and said surface.

30. The connection of claim 29, wherein each of said plug assemblies includes a cap having an annular inwardly projecting lip through which a connector body in which is disposed an end portion of the plug of said plug assembly extends, said connector body having an enlarged end portion in which is disposed said end portion of said plug, each said plug assembly also including a retaining clip which is disposed about said connector body adjacent to an inner side of said lip and a compression spring disposed about said connector body and engaging an outer side of said lip and an inner side of said enlarged portion of said connector body to urge said connector body and plug outwardly with said retaining clip holding said plug in said cap, said connector body also including a key which projects radially from and is attached to said enlarged portion thereof;

the key of said connector body in which is mounted said plug of said first plug assembly being disposed in said keyway of said buildout block with said plug of said first plug assembly disposed in said tubular portion of said buildout block, and said key of said connector body in which said plug of said second plug assembly is mounted being disposed in said keyway of said second tubular portion of said buildout.

31. The connector of claim 30, wherein said tubular portion of said buildout block and said second tubular portion of said buildout each includes two diametrically opposed pins which extend radially from said buildout block and from said buildout and which are received in latching slots which are provided in said caps in which said connector bodies are mounted to secure said plug assemblies to said buildout block and to said buildout and to prevent inadvertent rotary motion between said tubular portion of said buildout block and said cap of said plug assembly secured thereto and rotary motion between said second tubular portion of said buildout and said cap assembled thereto.

32. The connection of claim 31, wherein each said cap includes two diametrically opposed camming slots each of which extends from a free end of said cap inwardly helically about said cap, each of said camming slots communicating with an associated latching slot which extends from an inner end of the associated camming slot outwardly in a direction parallel to a longitudinal axis of said plug, each said cap also being provided with diametrically opposed entrances, each said entrance at a free end of said cap communicating with an outer end of an associated camming slot, said second tubular end portion including a longitudinally extending keyway which extends from an entrance end of said second tubular end portion and a pair of diametrically opposed latching pins projecting outwardly from said second tubular portion, said pins and said keyway being such that when a cap of a plug assembly was aligned with said buildout such that the key of said plug was aligned with said keyway in said second tubular portion of said buildout, said pins of the buildout were aligned with said camming slots of said cap and were capable of being moved along said entrances into said camming slots and into said latching slots to allow said second plug assembly to be secured to said buildout.

33. The connection of claim 32, which also includes an attenuating element comprising a plate-like portion being made of a material having an index of refraction substantially equal to that of glass, and a rail including a depending portion from which said plate-like portion is supported, said depending portion received in said slot of said sleeve with said plate-like portion disposed in said sleeve and with a portion of said rail disposed adjacent to an outer surface of said sleeve, said attenuating element being moved longitudinally slideably along said sleeve as each said plug was inserted into said sleeve.

34. The connection of claim 27, wherein the second tubular portion of said buildout including an outer portion which is threaded externally and a boss which is disposed concentrically within and spaced from said outer portion and wherein the tubular portion of said buildout block includes a longitudinally extending keyway therein and two diametrically opposed latching pins projecting from an outer surface thereof,

a second one of said plug assemblies including a plug extending from a connector body which is disposed about said boss of said second tubular portion of said buildout with said plug of said second plug assembly received in said sleeve and further including a cap which is slideably moveable, which is internally threaded and which is threadably engaged with said outer portion of said second tubular portion of said buildout;

and

a first one of said plug assemblies including a connector body from which a plug extends, said connector body of said first plug assembly having a key projecting therefrom and received in said keyway of said buildout block with said plug of said first plug assembly received in said tubular portion of said buildout block and in said sleeve, said first one of said plug assemblies also including a cap which is disposed concentrically about at least a portion of said connector body and which includes two camming slots and associated latching slots so that when said plug of said first plug assembly was inserted into said sleeve and said key was received in said keyway of said buildout block, each of said pins of said buildout block was caused to be moved along a camming slot and become disposed in the latching slot associated therewith to hold said cap of said first plug assembly assembled to said tubular portion of said buildout block.