Patent Description:
This invention relates to data center management, and in particular high speed data transport fiber cabling systems. Optical fibers allow for transmission of communications over longer distances and at higher bandwidths than wire cables. Optical fibers are also advantageous for communication systems because signals suffer less loss than wire cables and are immune to electromagnetic interference. Optical fibers are therefore often used for high bandwidth, long distance applications. One of the primary functions of a data center is to provide connections between incoming and outgoing optical fiber connections.

As demand for high bandwidth increases, it is advantageous to use smaller and/or higher capacity adapters to minimize the amount of data center rack space needed per optical fiber port. Due to this, many users of data centers are transitioning to smaller Local Connector adapters ("LC adapters") or Multi-fiber Push-on/Pull-off adapters ("MPO adapters"). Thus, a rack or enclosure which maximizes the number of LC or MPO adapters may be advantageous. Additionally, it may be advantageous if a rack or enclosure allowed for replacing LC adapters with MPO adapters which provide multi-fiber capabilities.

From time to time, maintenance or replacement of the adapters in an optical fiber system becomes necessary. However, disturbing the connection between optical fibers may cause a disruption in service over the optical wire. Therefore, it may also be advantageous to use a rack or enclosure system which disturbs a minimal number of optical fiber connections during maintenance on other adapters.

<CIT> discloses a prior art system having cassettes inserted into a tray where the cassettes are installed and uninstalled in a tilted configuration.

The present invention provides a method for loading a cassette into a high density enclosure according to claim <NUM>, a method for removing a cassette from a high density enclosure according to claim <NUM>, and a tray for removably installing and uninstalling a cassette according to claim <NUM>.

The high density fiber enclosure system <NUM> consists of chassis <NUM>, cassette trays <NUM>, cassette <NUM>, removable unification clip <NUM>, and removable trunk cable management system <NUM>. The enclosure system <NUM> may be made up of several chassis <NUM> stacked upon each other.

<FIG> illustrates the outside of chassis <NUM> with the front access door <NUM> closed. <FIG> illustrates the chassis <NUM> with the front access door <NUM> open. <FIG> illustrates the chassis <NUM> with the chassis cover <NUM> removed. <FIG>, <FIG>, and <FIG> also illustrate a slack management plate <NUM> which is mounted to the chassis <NUM>. As shown in <FIG>, <FIG>, <FIG>, and <FIG> the chassis <NUM> may include multiple sliding cassette trays <NUM>. In the embodiment shown, there are two cassette trays <NUM> positioned adjacent to each other in the same row. Further, in the embodiment shown, there are three rows of cassette trays <NUM>. Each cassette tray <NUM> may hold up to two cassettes <NUM>, such that up to a total of six cassette trays <NUM> and twelve cassettes <NUM> may be installed in one chassis <NUM>. Other embodiments are contemplated that may include more or less cassette trays <NUM> in the same row, and more or less rows of cassette trays within the chassis.

As shown in <FIG> and <FIG>, each cassette tray <NUM> includes multiple cassette tray rails <NUM>, which may slide in and out of chassis <NUM>. <FIG> illustrates an enhanced view of the front portion of two cassette tray rails <NUM>. <FIG> and <FIG> illustrate a unification clip <NUM> connected to two cassette tray rails <NUM>. A unification clip <NUM> may be used to join two cassette trays <NUM> together. Unification clip <NUM> is preferably a three-dimensional C-shaped structure, although unification clip <NUM> may also be D- or O-shaped, or of any other shape which allows unification clip <NUM> to join two cassette trays <NUM> together. As shown in <FIG>, <FIG>, <FIG>, <FIG>, the unification clip <NUM> has two mounting posts <NUM>, a cable management area <NUM>, a top opening <NUM>, and alignment posts <NUM>. Mounting posts <NUM> are configured to engage with unification clip slots <NUM> located on the outer cassette tray rail <NUM> or <NUM>. The mounting posts <NUM> are located on the rear portion of both sides of unification clip <NUM>. Cable management area <NUM> is defined by the lumen of the unification clip <NUM>-i.e. the empty space disposed within the unification clip <NUM>. Alignment posts <NUM> are located on the forward-most portion of the unification clip <NUM>. Alignment posts <NUM> engage with the front most portion of the cassette tray rails <NUM> such that the cable management area <NUM> of the unification clip <NUM> aligns with the front loops <NUM> of the cassette tray rails <NUM> or <NUM>. Top opening <NUM> is disposed at the rear top portion of the unification clip <NUM> and is large enough to allow a patch cable <NUM> to pass through. Thus, patch cables <NUM> may be managed by routing them through cable management area <NUM> of unification clip <NUM>. Because the cable management area <NUM> is aligned with the front loop <NUM> of the cassette tray rails <NUM> when the unification clip <NUM> is installed, the front loops <NUM> and cable management areas <NUM> work together to route patch cables <NUM>. As shown in <FIG>, when the unification clip <NUM> is installed the mounting posts <NUM> of the unification clip <NUM> each engage unification clip slots <NUM> on different cassette tray rails <NUM>. Similarly, alignment posts <NUM> of the unification clip <NUM> each engage with different cassette tray rails <NUM>, although they engage with the same two cassette tray rails <NUM> as the mounting posts <NUM>. In an embodiment, unification clip <NUM> may be removed from the cassette tray rails <NUM> by disengaging the alignment posts <NUM> as shown in <FIG>. The mounting posts <NUM> may also be disengaged as shown in <FIG>. <FIG> illustrates an isometric view of the unification clip <NUM> from the front and <FIG> is an isometric view of the unification clip <NUM> from the back.

<FIG> illustrate the cassette tray rails <NUM> in three different positions within a tray guide <NUM>. Cassette tray rails <NUM> may be disposed in the same three positions in tray guides <NUM> and <NUM>. Tray guides <NUM>, <NUM> and <NUM> include front, center, and rear detents <NUM>, <NUM>, and <NUM> which serve to position the cassette trays <NUM> in three separate positions-the home position, cord move or change position, and cassette replacement or addition position. Tray guides <NUM>, <NUM>, and <NUM> also each include three tray guide channels <NUM>. <FIG> illustrates the interaction of the spring protrusion <NUM> of the cassette tray rail <NUM> and the detents <NUM>, <NUM> and <NUM> of the tray guides <NUM>, <NUM>, and <NUM>. Spring protrusion <NUM> comprises a flat piece of flexible material with a protuberance <NUM> in its center. The spring protrusion <NUM> is preferably comprised of a flexible metal such as steel. The protuberance <NUM> of spring protrusion <NUM> is of a shorter length than detents <NUM>, <NUM>, and <NUM> in the direction of the cassette tray rail <NUM> or <NUM> and is preferably shaped to engage with detents <NUM>, <NUM>, and <NUM>. As shown in <FIG>, spring protrusion <NUM> flexes in the opposite direction of the protuberance <NUM> such that, when enough force is applied to slide the cassette tray <NUM> and the cassette <NUM> in the forward or rearward direction, the protuberance <NUM> escapes from detents <NUM>, <NUM>, and <NUM> and allows the cassette tray rails <NUM> or <NUM> to move freely along tray guides <NUM>, <NUM>, or <NUM> within tray guide channels <NUM>. When the protuberance <NUM> encounters another detent <NUM>, <NUM>, or <NUM>, the protuberance <NUM> engages with the detent <NUM>, <NUM>, or <NUM> and fixes the cassette tray <NUM> and the cassette <NUM> in position until enough force is applied to slide the cassette tray <NUM> and the cassette <NUM> to another position.

As further shown in <FIG> and <FIG>, the chassis <NUM> also includes forward limiting flanges <NUM>, rear limiting brackets <NUM>, a center forward limiting bracket <NUM>, a center rear limiting bracket <NUM>, and rack mounting brackets <NUM>. Forward limiting flanges <NUM> are protrusions on the left and right portions of the chassis <NUM> disposed proximate to the forward-most edge of the left tray guide <NUM> and right tray guide <NUM>. The protrusions of the forward limiting flanges <NUM> are bent <NUM> degrees toward the interior of the chassis <NUM> to engage with the cassette trays <NUM> in the cassette replacement or addition position. Rear limiting brackets <NUM> are brackets disposed or attached proximate to the rearward-most edge of the left tray guide <NUM>, right tray guide <NUM>, and center tray guide <NUM>. The rear limiting brackets engage with the cassette trays <NUM> in the home position. The center rear limiting brackets <NUM> attached to the center tray guide <NUM> are shaped to engage with both of the cassette trays <NUM> located in the same row of the chassis <NUM> in the home position. The center forward limiting bracket <NUM> is also attached to the center tray guide <NUM> and is shaped to engage with both of the cassette trays <NUM> located in the same row of the chassis <NUM> in the cassette replacement or addition position. Once the cassette trays <NUM> are installed within tray guides <NUM>, <NUM>, and <NUM> and the rear limiting brackets <NUM>, center forward limiting bracket <NUM>, and center rear limiting bracket <NUM> are installed on the chassis <NUM>, cassette trays <NUM> are maintained within the chassis <NUM> and cannot be removed without first removing the center forward limiting bracket <NUM> or the rear limiting brackets <NUM> and center rear limiting bracket <NUM>.

<FIG> and <FIG> illustrate the chassis <NUM> with the cassette trays <NUM> and the cassettes <NUM> removed. As shown in <FIG>, rack mounting brackets <NUM> provide the connection between the chassis <NUM> and the high density fiber enclosure system <NUM>. As shown in <FIG>, the rack mounting brackets <NUM> may contain two rows of countersink thru holes <NUM> which allow the rack mounting bracket <NUM> to be adjustably mounted to the chassis <NUM>. A variety of mounting location options are provided by the two rows of countersink thru holes <NUM>, allowing the installer to align the front portion of the chassis <NUM> with the front portion of the high density fiber enclosure system <NUM>. The rack mounting brackets <NUM> also include slotted and cut openings <NUM> on the top and bottom of the forward-most portion of the rack mounting brackets <NUM>. Notably, the forward-most portion of the rack mounting brackets <NUM> may be bent <NUM> degrees such that the slotted and cut openings <NUM> face the front of the chassis <NUM> when installed. The slotted and cut openings <NUM> allow the chassis <NUM> to be pre-installed by allowing the installer to rest the chassis <NUM> on two pre-installed screws located on the high density fiber enclosure system <NUM>. The pre-installed screws may then be tightened to install the chassis <NUM> in the high density fiber enclosure system <NUM>.

<FIG> illustrates an embodiment of the slack management plate <NUM> which includes cutouts <NUM>. Slack management plate <NUM> may also optionally include a divider <NUM> as shown in <FIG>. Divider <NUM> may be formed of a removable or permanent wall or other structure disposed perpendicular to the plane of slack management plate <NUM> which allows a user to organize trunk cable furcation legs <NUM>. One embodiment of divider <NUM> is shown in <FIG>.

<FIG> illustrates the center tray guide <NUM> removed from the chassis <NUM>.

Left tray guides <NUM> and right tray guides <NUM> are attached to the chassis <NUM> as shown in <FIG>, <FIG>, and <FIG>. In particular, a left tray guide <NUM> is attached to the left side wall <NUM> of the chassis <NUM>, a right tray guide <NUM> is attached to the right side wall <NUM> of the chassis <NUM>. A center tray guide <NUM> is attached to chassis <NUM>. Alternatively, a center tray guide <NUM> may be integrally formed such that it comprises both a left tray guide <NUM> and right tray guide <NUM>. Left tray guides <NUM> and right tray guides <NUM> are mirror images of one another. Each of the tray guides <NUM>, <NUM> and <NUM> have three tray guide channels <NUM> which serve to support the cassette trays <NUM> as they slide in and out of the chassis <NUM>.

<FIG> further illustrate rear limiting brackets <NUM> and center rear limiting brackets <NUM>. Rear limiting brackets <NUM> are brackets disposed or attached proximate to the rearward-most edge of the left tray guide <NUM>, right tray guide <NUM>, and center tray guide <NUM>. The rear limiting brackets engage with the cassette trays <NUM> in the home position. The center rear limiting brackets <NUM> attached to the center tray guide <NUM> are shaped to engage with both of the cassette trays <NUM> located in the same row of the chassis <NUM> in the home position. Once the cassette trays <NUM> are installed within tray guides <NUM>, <NUM>, and <NUM> and the limiting brackets <NUM> and <NUM> are installed on the chassis <NUM>, cassette trays <NUM> are maintained within the chassis <NUM> and cannot be removed without first removing the rear limiting brackets <NUM> and <NUM>.

<FIG> illustrate a right tray guide <NUM>. Right tray guide <NUM> comprises a plurality of tray guide channels <NUM> running lengthwise down one side of the tray guide <NUM> and approximately parallel to one another. In one embodiment three tray guide channels <NUM> comprise a right tray guide <NUM>. Additionally, each tray guide channel <NUM> includes a front detent <NUM>, a center detent <NUM>, and a rear detent <NUM> as shown in <FIG>.

<FIG> illustrate a center tray guide <NUM>. Center tray guide <NUM> comprises a plurality of tray guide channels <NUM> running lengthwise down both sides of the tray guide <NUM> and approximately parallel to one another. In one embodiment three tray guide channels <NUM> disposed on each side of the center tray guide <NUM> comprise a center tray guide <NUM>. Additionally, each tray guide channel <NUM> includes a front detent <NUM>, a center detent <NUM>, and a rear detent <NUM> as shown in <FIG>.

<FIG> illustrate a left tray guide <NUM>. Left tray guide <NUM> comprises a plurality of tray guide channels <NUM> running lengthwise down one side of the tray guide <NUM> and approximately parallel to one another. In one embodiment three tray guide channels <NUM> comprise a left tray guide <NUM>. Additionally, each tray guide channel <NUM> includes a front detent <NUM>, a center detent <NUM>, and a rear detent <NUM> as shown in <FIG>. In an embodiment, left tray guides <NUM> and right tray guides <NUM> are mirror images of one another.

As shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG> and <FIG>, each cassette tray <NUM> consists of a tray base <NUM>, cassette tray rails <NUM>, and cassette flex beam <NUM>. The tray base <NUM> is preferably comprised of a sheet metal base. The tray base <NUM> includes a front recessed area <NUM> which provides maximum allowable reach for an installer or user to access patch cords <NUM> (not shown). The tray base <NUM> also has a right cassette bay <NUM> and a left cassette bay <NUM>. Each cassette bay <NUM> and <NUM> includes a cassette opening <NUM> which allows an installer to access installed patch cords <NUM> from the bottom and top of the cassette tray <NUM>. Finally, left and right cassette tray rails <NUM> and <NUM> are disposed upon the cassette tray <NUM> within each cassette bay <NUM> and <NUM> such that each cassette bay <NUM> and <NUM> includes a left cassette tray rail <NUM> disposed on the left side of the cassette bay <NUM>, and a right cassette tray rail <NUM> disposed on the right side of the cassette bay <NUM>. Alternatively, if a center cassette tray rail <NUM> is used, a right cassette bay <NUM> may have a cassette tray rail <NUM> disposed on the right side of right cassette bay <NUM> and a center cassette tray rail <NUM> disposed on the left side of right cassette bay <NUM>, and a left cassette bay <NUM> may have a left cassette tray rail <NUM> disposed on the left side of left cassette bay <NUM> and a center cassette tray rail <NUM> disposed on the right side of left cassette bay <NUM>. As further discussed herein with reference to the use of the high density fiber enclosure system <NUM>, <FIG> show the cassette tray <NUM> in different stages of removal of a cassette <NUM> from the front of the chassis <NUM>.

As shown in <FIG> and <FIG>, the front patch cord management loop <NUM> is disposed at the forward-most portion of the cassette tray rail <NUM>. The front patch cord management loop <NUM> provides an organization structure for patch cords <NUM> consisting of a front loop <NUM> and an opening <NUM> to route patch cords <NUM> through. The opening <NUM> allows the patch cords <NUM> to travel from right to left or left to right through the front loop <NUM>. The front loop <NUM> has a slot <NUM> on its topmost portion which is wide enough to allow patch cords <NUM> to pass through. Therefore, patch cords <NUM> may enter and leave the front loop <NUM> via the slot <NUM> without either end of the patch cord <NUM> being disconnected. A unification clip slot <NUM> is located just behind the front patch cord management loop <NUM> on the cassette tray rail <NUM> or <NUM>. Unification clip slot <NUM> is located on the outside of the cassette tray rail <NUM> or <NUM>. Center cassette tray rails <NUM> do not include unification clip slots <NUM>. Disposed further rearward on the cassette tray rail <NUM> is the front post stop area <NUM>. The front post stop area <NUM> interacts with the cassette front post <NUM> to properly seat the cassette <NUM> into the cassette tray rail <NUM>. Disposed proximate and to the rear of the front post stop area <NUM> is the post stops discontinuity <NUM>. The post stops discontinuity <NUM> is a smooth portion of the cassette tray rail <NUM> which ensures the front post <NUM> and rear post <NUM> of the cassette <NUM> do not engage with the cassette tray rail <NUM> within the post stops discontinuity <NUM>. Disposed proximate and to the rear of the post stops discontinuity <NUM> is the rear post stop <NUM>. The rear post stop <NUM> is a notch designed to interact with the rear post <NUM> of the cassette <NUM> such that the rear post stop <NUM> captures the rear post <NUM> on three sides and blocks the cassette <NUM> from moving upwards or rearwards.

As further shown in <FIG> and <FIG>, a cassette centering feature <NUM> is also integrated into the cassette tray rails <NUM>. The cassette centering feature <NUM> is a triangular-shaped protuberance located on the bottom portion of the cassette tray rail <NUM> just proximate to and rear of the front post stop area <NUM>. The cassette centering feature <NUM> is designed such that, when a cassette <NUM> is loaded from the rear of the chassis <NUM>, an outer shuttered LC adapter <NUM> or MPO patch cord adapter <NUM> makes contact with the cassette centering feature <NUM> and, due to the continued forward movement of the cassette <NUM>, urges the cassette <NUM> into proper alignment with the cassette tray rails <NUM> or <NUM> such that the front posts <NUM> engage with the front post stop areas <NUM> and the rear posts <NUM> engage with the rear post stops <NUM> essentially simultaneously.

<FIG> illustrates a left cassette tray rail <NUM>, right cassette tray rail <NUM>, and center cassette tray rail <NUM>. The cassette tray rails <NUM> each consist of a support rib <NUM>, spring protrusion <NUM>, front post stop area <NUM>, post stops discontinuity <NUM>, and rear post stop <NUM>. Left cassette tray rails <NUM> and right cassette tray rails <NUM> may be mirror images of one another. In an embodiment, a center cassette tray rail <NUM> consists of a spring protrusion <NUM>, front post stop area <NUM>, post stops discontinuity <NUM>, and rear post stop <NUM> on both sides of center cassette tray rail <NUM>. In an alternative embodiment, a center cassette tray rail <NUM> comprises a left cassette tray rail <NUM> and right cassette tray rail <NUM> disposed back-to-back. Center cassette tray rails <NUM> do not include support ribs <NUM>. Left cassette tray rails <NUM> travel within a left tray guide <NUM> and right cassette tray rails <NUM> travel within a right tray guide <NUM>. The support rib <NUM> of the cassette tray rail <NUM> travels along the top portion of a tray guide <NUM>, <NUM>, or <NUM> to support the cassette tray rail <NUM> or <NUM> and cassette tray <NUM>. The support rib <NUM> of the cassette tray rail <NUM> or <NUM> extends along the bottom portion of the cassette tray rail <NUM> or <NUM> from the rear of the cassette tray rail <NUM> to <NUM> to a front patch cord management loop <NUM>.

As shown in <FIG>, additional features of the cassette tray rail <NUM> are designed to facilitate the movement of the cassette tray <NUM> and cassette <NUM> in and out of the high density fiber enclosure <NUM> in three different positions. The stopping block <NUM> interacts with the forward limiting flange <NUM> to limit forward movement of the cassette <NUM> at the cassette replacement or addition position. The cassette replacement or addition position is the forward-most disposition of the cassette tray <NUM> and cassette <NUM> and allows a user to replace or add cassettes to the chassis <NUM>. The stopping block <NUM> (as shown in <FIG>) is disposed near the rear of the cassette tray rail <NUM> such that the forward motion of the cassette <NUM> is halted at the cassette replacement or addition position.

As shown in <FIG>, a spring protrusion <NUM> is disposed on the most rearward portion of the cassette tray rails <NUM> and <NUM>. Center cassette tray rails <NUM> do not include spring protrusions <NUM>. The spring protrusion <NUM> interferes with the detents <NUM>, <NUM>, and <NUM> in order to position the cassette <NUM> and cassette tray <NUM> in the home, cord move or change, and cassette replacement or addition positions. In particular, the spring protrusion <NUM> is disposed within the front detent <NUM> at the cassette replacement or addition position. The spring protrusion <NUM> is disposed within the center detent <NUM> in the cord move or change position. Finally, the spring protrusion <NUM> is disposed within the rear detent <NUM> in the home position. Spring protrusion <NUM> comprises a flat piece of flexible material with a protuberance <NUM> in its center. The spring protrusion <NUM> is preferably comprised of a flexible metal such as steel. The protuberance <NUM> of spring protrusion <NUM> is of a shorter length than detents <NUM>, <NUM>, and <NUM> in the direction of the cassette tray rail <NUM> or <NUM> and is preferably shaped to engage with detents <NUM>, <NUM>, and <NUM>. As shown in <FIG>, spring protrusion <NUM> flexes in the opposite direction of the protuberance <NUM> such that, when enough force is applied to slide the cassette tray <NUM> and cassette <NUM> in the forward or rearward direction, the protuberance <NUM> escapes from detents <NUM>, <NUM>, and <NUM> and allows the cassette tray rails <NUM> or <NUM> to move freely along tray guides <NUM>, <NUM>, or <NUM>. When the protuberance <NUM> encounters another detent <NUM>, <NUM>, or <NUM>, the protuberance <NUM> engages with the detent <NUM>, <NUM>, or <NUM> and fixes the cassette tray <NUM> and cassette <NUM> in position until enough force is applied to slide the cassette tray <NUM> and cassette <NUM> to another position.

As shown in <FIG>, cassette flex beam <NUM> is formed of a beam shaped to engage with the cassette <NUM> such that the cassette <NUM> is securely installed in the cassette tray <NUM> and no unwanted motion of the cassette <NUM> within the cassette tray <NUM> occurs. Left cassette flex beams <NUM> are disposed on left cassette tray rails <NUM>; right cassette flex beams <NUM> are disposed on right cassette tray rails <NUM>. Left cassette flex beams <NUM> are mirror images of right cassette flex beams <NUM>. Cassette flex beam <NUM> has a beam portion <NUM>, catch wall <NUM>, front lead-in <NUM>, and mounting hole <NUM>. The beam portion <NUM> of cassette flex beam <NUM> is disposed between the catch wall <NUM> and mounting hole <NUM> and is generally horizontal. The catch wall <NUM> of cassette flex beam <NUM> is disposed on the rearmost portion of the beam portion <NUM> and is generally vertical. The catch wall <NUM> includes a divot <NUM> which is shaped to engage with front post <NUM> of the cassette <NUM> such that catch wall <NUM> prohibits the cassette <NUM> from upward movement until sufficient upward force is applied to the cassette <NUM> to deflect the flex beam <NUM>. Catch wall <NUM> also applies rearward pressure on the front post <NUM> of the cassette <NUM> to minimize rattling or other unwanted movement while the cassette <NUM> is in an installed position. Front lead-in <NUM> is a portion of the catch wall <NUM> which protrudes rearwardly from the rest of catch wall <NUM>. Front lead-in <NUM> guides the front post <NUM> of the cassette <NUM> into the divot <NUM> during front cassette installation. Front lead-in <NUM> also forms the top portion of divot <NUM>. Mounting hole <NUM> is disposed on the front-most portion of the beam portion <NUM> of cassette flex beam <NUM>. Mounting hole <NUM> is configured to mount the flex beam <NUM> on the cassette tray rail <NUM> or <NUM> when the flex beam <NUM> is assembled with the cassette tray rail <NUM>. Cassette flex beam <NUM> may also be integrally formed with a cassette tray rail <NUM>. If cassette flex beam <NUM> is integrally formed with cassette tray rail <NUM>, mounting hole <NUM> is not necessary.

Two different types of cassettes <NUM> are disclosed for use with the high density fiber enclosure system <NUM>, an LC-MPO cassette <NUM> (<FIG> and <FIG>) and an MPO fiber adapter panel ("herein after "MPO FAP") <NUM> (<FIG>, <FIG>, <FIG>, and <FIG>), although other types of cassettes <NUM> may also be used. Cassettes <NUM> used with the high density fiber enclosure system <NUM> may have a cassette body <NUM>, a cassette cover <NUM>, cassette front posts <NUM>, cassette rear posts <NUM>, cassette rear post release latches <NUM>, and cassette rear release latch stops <NUM>. Cassette body <NUM> is of generally rectangular shape, and has a base <NUM>, right side <NUM>, and left side <NUM>. Right and left sides <NUM> and <NUM> have a right wall <NUM> and left wall <NUM>, respectively, and are attached at a generally <NUM> degree angle to base <NUM> at the right and left sides <NUM> and <NUM> of base <NUM>. A cassette cover <NUM> is provided which extends parallel to the base <NUM> of the cassette body <NUM> from the right wall <NUM> to the left wall <NUM>. Cassette cover <NUM> is provided to protect the components of cassette <NUM>. Cassette <NUM> may also include top side indicator <NUM> and bottom side indicator <NUM>. Top side indicator <NUM> is disposed on the outside portion of cassette cover <NUM> and indicates that, when visible as viewed from above an installed cassette <NUM>, the cassette <NUM> is disposed in an upright first position (see <FIG>). Bottom side indicator <NUM> is disposed on the outside portion of cassette body <NUM> and indicates that, when visible as viewed from above an installed cassette <NUM>, the cassette <NUM> is disposed in an upside down second position (see <FIG>). Top side indicator <NUM> and bottom side indicator <NUM> may be comprised of raised embossing, a plate or label attached to the cassette <NUM>, a painted area, or any other form of marking. Top side indicator <NUM> and bottom side indicator <NUM> may be a word, number, phrase, symbol, or combination thereof sufficient to inform the user whether the cassette <NUM> is in the upright first position or upside down second position. Alternatively, a recess <NUM> may be provided on the top and bottom sides of cassette <NUM> to allow a user a location to affix his or her own label to both sides of cassette <NUM>. Recess <NUM> may be of any shape, but is preferably of a rectangular shape.

As described above, cassette front posts <NUM> are designed to interact with the cassette tray rail front post stop areas <NUM> such that at the installed position, the cassette front posts <NUM> rest inside the cassette tray rail front post stop areas <NUM> and are blocked from forward movement by a catch wall <NUM> of cassette flex beam <NUM> located in the cassette tray rail front post stop area <NUM>. Cassette rear posts <NUM> are designed to interact with the cassette tray rail rear post stops <NUM> in the cassette installed position. At the cassette installed position the cassette rear posts <NUM> are maintained inside the cassette tray rail rear post stops <NUM> blocking rearward and upward movement of the cassette <NUM>.

Shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>, cassette rear post release latches <NUM> are designed to disengage the cassette rear posts <NUM> from the cassette tray rail rear post stops <NUM> when a user desires to uninstall a cassette <NUM>. Cassette rear post release latches <NUM> are preferably comprised of a protrusion <NUM> from the rear of cassette rear post <NUM> and an opening <NUM> between the body of the cassette <NUM> and the rear post <NUM>. Cassette rear post release latches <NUM> are comprised of a resilient material which allows the rear post <NUM> to flex inwardly when pressure is placed on cassette rear post release latches <NUM>. When a user desires to uninstall a cassette <NUM>, the user places inwardly directed pressure on cassette rear post release latch <NUM>. The cassette rear post <NUM> then travels inwardly and disengages with the cassette tray rail rear post stop <NUM>. Cassette <NUM> may then be removed from the cassette tray <NUM>. Cassette rear post release latch stop <NUM> is disposed on the body of the cassette <NUM> in a position to engage with the cassette rear post release latch <NUM> when inwardly directed pressure is placed on cassette rear post release latches <NUM>. The cassette rear post release latch stop <NUM> is positioned to allow the cassette rear post <NUM> to travel a sufficient distance in the inward direction to disengage from the cassette tray rail rear post stop <NUM> while blocking the cassette rear post <NUM> from over traveling in the inward direction. Blocking over travel of cassette rear post <NUM> in the inward direction may minimize unnecessary material fatigue and/or the failure of cassette rear post release latch <NUM>, prolonging the useable life of cassette <NUM>. Cassette rear post release latch stop <NUM> may be comprised of a post or other protrusion extending from the body of the cassette <NUM>. Alternatively, cassette rear post release latch stop <NUM> may be part of the body of the cassette <NUM>.

As noted above, at least two different types of cassettes <NUM> may be used in the high density fiber enclosure system <NUM>-LC-MPO cassettes <NUM> (<FIG> and <FIG>) and MPO FAP <NUM> (<FIG>, <FIG>, <FIG>, and <FIG>). In addition to the cassette features described above, LC-MPO cassettes <NUM> also include a front LC mounting face <NUM>, shuttered LC adapters <NUM>, rear MPO mounting window <NUM>, and an MPO trunk adapter <NUM>. The front LC mounting face <NUM> is located on the front portion of LC-MPO cassette <NUM> and provides a location for mounting shuttered LC adapters <NUM>. Shuttered LC adapters <NUM> are standard adapters known and used in the art for connecting patch cords <NUM> within data management centers, for example, shuttered LC adapters. Alternatively, for example, shuttered LC adaptors or non-shuttered LC adaptors may be used. Front LC mounting face <NUM> provides space for up to <NUM> shuttered LC adapters <NUM>. MPO trunk adapter <NUM> is located at the rear of cassette body <NUM> and connects to trunk cable furcation legs <NUM> which each include a dust cap <NUM>. Dust caps <NUM> are removed from trunk cable furcation legs <NUM> prior to installation of trunk cable furcation legs <NUM> in MPO trunk adapters <NUM>. MPO trunk adapters <NUM> are standard adapters known in the art, for example Panduit's SC style simplex form adapter. Rear MPO mounting windows <NUM> are located on the rear portion of cassette body <NUM> and each provide a location on the cassette body <NUM> for mounting MPO trunk adapters <NUM> to the cassette body <NUM>. In one embodiment, four MPO mounting windows <NUM> are located on the cassette body <NUM> which allows up to four MPO trunk adapters <NUM> to be mounted on cassette body <NUM>.

As an alternative to LC-MPO cassettes <NUM> (or other types of cassettes <NUM>), MPO FAP <NUM> may be used as shown in <FIG>, <FIG>, <FIG>, and <FIG>. In addition to the cassette features described above, MPO FAP <NUM> also include a front MPO mounting face <NUM>, MPO patch cord adapters <NUM>, bottom window <NUM>, and population feature <NUM>. Front MPO mounting face <NUM> is located on the front portion of cassette body <NUM> and provides a location for mounting up to six MPO patch cord adapters <NUM>. MPO patch cord adapters <NUM> are configured to connect patch cords <NUM> with the cassette <NUM>. Up to six MPO patch cord adapters <NUM> provide a location for connecting up to six trunk cable furcation legs <NUM> which each have a dust cap <NUM>. Dust cap <NUM> is removed from trunk cable furcation legs <NUM> prior to installing trunk cable furcation legs <NUM> into MPO patch cord adapters <NUM>. Bottom windows <NUM> are disposed on the cassette body base <NUM> just behind the front MPO mounting face <NUM>. Bottom windows <NUM> allow a user to access the MPO trunk cable furcation legs <NUM> from the top and bottom to allow a user to connect or disconnect trunk cable furcation legs <NUM> to and from MPO trunk adapters <NUM>.

As shown in <FIG>, population feature <NUM> provides a trunk cable furcation legs <NUM> capture and routing system for installing, adding, or changing trunk cable furcation legs <NUM> attached to MPO trunk adapters <NUM> in an MPO FAP <NUM>. Population feature <NUM> is comprised of a plurality of rows of offset pegs <NUM> disposed on the base <NUM> of the MPO FAP <NUM>. Pegs <NUM> may be of any shape, including cylindrical, triangular, rectangular, etc. Preferably, three to four pegs <NUM> are provided in each row. When installing a trunk cord <NUM>, the user routes the trunk cable furcation legs <NUM> through the rows of pegs <NUM>. The offset nature of the rows of pegs <NUM> loosely holds the trunk cable furcation legs <NUM> in position while cassette <NUM> is translated via the movement of the cassette tray <NUM> to the cassette remove or addition position. Once cassette tray <NUM> is in the cassette remove or addition position, the MPO connector <NUM> is disengaged from the pegs <NUM> and trunk cable furcation legs <NUM> are extended to reach the MPO trunk adapters <NUM>, at which point the MPO connector dust cap <NUM> may be removed. Then the trunk cable MPO Connectors <NUM> are connected to MPO trunk adapters <NUM>; the trunk cable furcation legs <NUM> may remain routed through the rows of pegs <NUM>.

<FIG>, <FIG>, <FIG>, and <FIG> illustrate multiple embodiments of cable management within the cassette trays <NUM>. <FIG> illustrates a unidirectional cable management scheme in which the patch cables <NUM> are routed through the front patch cord management loops <NUM> in one direction. As shown in <FIG> and <FIG>, a unification clip <NUM> is typically installed when using a unidirectional scheme. <FIG> illustrates an overhead view of cable flow as shown in <FIG>. <FIG> illustrates a split routing cable management scheme in which the patch cables <NUM> are routed through the front patch cord management loops <NUM> in two separate directions. Specifically, as shown in <FIG>, the patch cables <NUM> exiting a cassette tray <NUM> installed on the left side of a chassis <NUM> are routed to the left of the chassis <NUM>, and patch cables <NUM> exiting a cassette tray <NUM> installed on the right side of a chassis <NUM> are routed to the right side of the chassis <NUM>. <FIG> illustrates an overhead view of cable flow shown in <FIG>.

As illustrated in <FIG>, the high density fiber enclosure system <NUM> may also include a trunk cable management system <NUM>. The trunk cable management system <NUM> includes a slack management plate <NUM> and a vertical cable manager <NUM>.

As illustrated in <FIG> (as well as <FIG>), the slack management plate <NUM> is mounted to a chassis <NUM> by attaching the front most portion of the slack management plate <NUM> to the rear most portion of the left and right side walls of the chassis <NUM> and <NUM> using spring loaded fasteners <NUM> and support pin <NUM> (shown in <FIG>). The support pin <NUM> is connected to the slack management plate <NUM> such that the slack management plate <NUM> may be rotated about the support pin <NUM>. The spring loaded fasteners <NUM> secure the slack management plate <NUM> to the left and right side walls of the chassis <NUM> and <NUM>. The slack management plate <NUM> provides a relatively level surface upon which the portion of trunk cable furcation legs <NUM> which exit the chassis <NUM> may rest to reduce the strain upon the trunk cable furcation legs <NUM>. In addition, the slack management plate <NUM> allows for management of trunk cable furcation legs <NUM> slack which is adequate to allow full extension of cassette trays <NUM> to further reduce the strain upon the trunk cable furcation legs <NUM>. The slack management plate <NUM> preferably includes cutouts <NUM> which allow the pins, fasteners, separators, cable ties, and/or other features for removably and securely organizing the trunk cable furcation legs <NUM> as they rest upon the slack management plate <NUM>. Cutouts <NUM> may be of any shape, but as shown in <FIG> they are preferably of a square or rectangular shape. Preferably the trunk cable furcation legs <NUM> installed on one cassette <NUM> may be disposed on one side of divider <NUM> and the trunk cable furcation legs <NUM> installed in the other cassette <NUM> may be disposed on the other side of divider <NUM>. A slack management plate <NUM> is preferably mounted to each chassis <NUM>.

As shown in <FIG>, <FIG> and <FIG>, the vertical cable manager <NUM> is mounted to the side of the high density fiber enclosure system <NUM> and provides structure for organizing and reducing the strain upon the trunk cables <NUM> and trunk cable furcation legs <NUM>. The vertical cable manager <NUM> consists of transition management panels <NUM> with attachment points <NUM> and panel attachment clips <NUM>, cable management fingers <NUM>, and transition bundling clips <NUM> with transition indentations <NUM> and bundling clip fasteners <NUM>. As shown in <FIG>, transition management panels <NUM> are mounted on the trunk cable management system <NUM> such that they are generally perpendicular and offset to the slack management plates <NUM>. The transition management panels <NUM> include attachment points for transition bundling clips <NUM>. As shown in <FIG>, attachment points for transition bundling clips <NUM> are slots configured within the transition management panels <NUM> such that transition bundling clips <NUM> securely engage transition management panels <NUM>, or allow pins, fasteners, separators, cable ties, and/or other features for removably and securely organizing the trunk cables <NUM> or trunk cable transitions <NUM>. A plurality of attachment points <NUM> are preferably disposed on each transition management panel <NUM>, and attachment points <NUM> are preferably arranged in a number of rows of multiple attachment points <NUM> such that transition bundling clips <NUM> may be attached in a staggered fashion to transition management panel <NUM>. Panel attachment clips <NUM> are generally located at each corner of generally rectangular shaped transition management panels <NUM> and are configured such that the transition management panels <NUM> are securely affixed to cable management fingers <NUM>.

As shown in <FIG>, <FIG>, and <FIG>, cable management fingers <NUM> protrude from the vertical cable manager <NUM> toward the front and rear of chassis <NUM>. The cable management fingers <NUM> preferably include a perpendicular portion at the end of the fingers <NUM> furthest from chassis <NUM> to more securely confine cables. Transition management panels <NUM> are preferably mounted upon cable management fingers <NUM> such that each panel attachment clip <NUM> of each transition management panel <NUM> is disposed on a different cable management finger <NUM>. The transition management panels <NUM> can be secured to the cable management fingers <NUM> at any point along the length of the cable management fingers <NUM>, which allows a user to stagger the cable management panels <NUM> such that some transition management panels <NUM> are located closer to the vertical cable manager <NUM> than other transition management panels <NUM>. This allows a greater number of trunk cables <NUM> and trunk cable furcation legs <NUM> to be better managed in a smaller area with less strain to the trunk cables <NUM>.

As shown in <FIG>, <FIG>, <FIG>, and <FIG> transition bundling clips <NUM> are mounted upon transition management panels <NUM> via attachment points <NUM>. As shown in <FIG>, transition bundling clips <NUM> include a transition indentation <NUM>. The transition indentation <NUM> is preferably disposed within trunk cable transition <NUM> between trunk cables <NUM> and trunk cable furcation legs <NUM> such that the trunk cable transition <NUM> is securely housed within transition indentation <NUM> and strain upon the transition is reduced or eliminated.

As shown in <FIG> and <FIG>, panel attachment clips <NUM> are preferably one of two types of clips-snap fit panel attachment clips <NUM> or loose fit panel attachment clips <NUM>. Preferably two snap fit panel attachment clips <NUM> are located on one side of transition management panels <NUM> and two loose fit panel attachment clips <NUM> or snap fit panel attachment clips <NUM> are located on the other side of the transition management panel <NUM>. As shown in <FIG>, bundling clip fasteners <NUM> engage the transition bundling clips <NUM> and transition management panels <NUM> to securely affix the transition bundling clips <NUM> to a transition management panel <NUM>.

In another embodiment for managing trunk cables <NUM>, trunk cable furcation legs <NUM>, trunk cable transition <NUM>, shown in <FIG>, transition management panels 710a may be mounted upon the rack equipment rails <NUM> of the high density fiber enclosure system <NUM>. As shown in <FIG>, transition management panels 710a include attachment points <NUM> as well as slotted and cut openings 714a for securing the transition management panels 710a directly to the rack equipment rails <NUM>. Transition management panels 710a may be mounted upon the rack equipment rails <NUM> of the high density fiber enclosure system <NUM> such that the transition management panels 710a extend along the side of the high density fiber enclosure system <NUM> or along the rear portion of high density fiber enclosure system <NUM>. The user may secure the trunk cable transitions <NUM> between trunk cables <NUM> and trunk cable furcation legs <NUM> using transition bundling clips <NUM> which are mounted upon transition management panels 710a via attachment points <NUM> and secured with bundling clip fasteners <NUM>. Alternatively, the user may secure the trunk cable transitions <NUM> upon transition management panels 710a through attachment points <NUM> with fasteners known in the art, for example hook and loop tape.

Use of the above features of the high density fiber enclosure system <NUM> will now be described.

To connect a chassis <NUM> to a high density fiber enclosure system <NUM>, a user connects a rack mounting bracket <NUM>, for example as shown in <FIG>, <FIG>, to the chassis <NUM> via the countersink thru holes <NUM> with a chassis screw <NUM>. Several rows of countersink thru holes <NUM> are provided to allow the user to select the appropriate countersink thru hole <NUM> that results in the alignment of the front of the chassis <NUM> with the front of the high density fiber enclosure system <NUM> in the installed position. The user inserts the chassis screw <NUM> into the countersink thru hole <NUM> and into the chassis <NUM> to attach the mounting bracket <NUM>.

To mount the chassis <NUM> to the high density fiber enclosure system <NUM>, for example as shown in <FIG>, the user pre-installs screws into the retainment holes <NUM> disposed on the high density fiber enclosure system <NUM> without fully tightening the screws. The user hooks the rack mounting bracket <NUM> onto the pre-installed screws via the slotted and cut openings <NUM>, as shown in <FIG> for example, and allows the chassis <NUM>, which is attached to the mounting bracket <NUM>, to rest in a generally horizontal position on the slotted and cut openings <NUM>. Once the chassis <NUM> is in the desired position, the user then tightens pre-installed screws to secure the chassis <NUM> into the high density fiber enclosure system <NUM>.

A user may load cassettes <NUM> into the cassette trays <NUM> of the chassis <NUM> from either the rear or front of the chassis <NUM>. To load a cassette <NUM> into the chassis <NUM> from the rear of the chassis <NUM>, a user may insert the cassette <NUM> into a right or left cassette bay <NUM> or <NUM>, for example as shown in <FIG>, with the front portion of the cassette <NUM>-i.e. the portion of the cassette <NUM> nearest the cassette front posts <NUM>-loaded into the cassette bay <NUM> or <NUM> first. Cassette front posts <NUM> are narrower than cassette rear posts <NUM> and therefore do not engage the rear post stops <NUM> as they pass the rear post stops <NUM>. The user may advance the cassette <NUM> into the cassette bay <NUM> or <NUM> until the cassette rear post <NUM> engages with the rear post stops <NUM>. When the cassette rear post <NUM> engages with the rear post stops <NUM>, the cassette <NUM> cannot be advanced further into cassette bay <NUM> or <NUM>. At the same time the cassette rear posts <NUM> engage the rear post stops <NUM>, the cassette front posts <NUM> engage with the catch wall <NUM> of the cassette flex beam <NUM>. The catch wall <NUM> of the cassette flex beam <NUM> holds the cassette front posts <NUM> such that they cannot be advanced further with respect to the cassette bay <NUM> or <NUM>. The catch wall <NUM> of the cassette flex beam <NUM> may apply rearward pressure on the cassette front post <NUM> to insure the cassette rear posts <NUM> are securely engaged with rear post stops <NUM> and the cassette <NUM> does not rattle or otherwise move unintentionally. The user then may connect patch cords <NUM> and trunk cable furcation legs <NUM> to the cassette <NUM> as necessary. The user may also then route patch cords <NUM> and trunk cable furcation legs <NUM> as described below. Alternatively the user may install trunk cable furcation legs <NUM> into the cassette <NUM> prior to loading cassette <NUM> into cassette bay <NUM> or <NUM>.

To load a cassette <NUM> from the front of the high density fiber enclosure <NUM>, a user first advances the cassette tray <NUM> to the cassette addition or replacement position as described below. The user then inserts the cassette <NUM> into a right or left cassette bay <NUM> or <NUM>, for example as shown in <FIG> and <FIG>, from the front of the chassis <NUM> with the rear portion-i.e. the portion of the cassette nearest the cassette rear posts <NUM>-loaded into the cassette bay <NUM> or <NUM> first by placing the rear of the cassette <NUM> on the base <NUM> of the cassette tray <NUM> such that the cassette rear posts <NUM> are located between the front post stop areas <NUM> and rear post stops <NUM> of the cassette tray rails <NUM>. The cassette <NUM> is slightly tilted upward such that the front portion of the cassette <NUM> is higher than the rear portion of the cassette <NUM>. The user then advances the cassette <NUM> in the rearward direction, maintaining the tilt of the cassette <NUM> as the front portion of the cassette <NUM> is in a somewhat higher position than the rear portion of the cassette <NUM>, until the rear posts <NUM> engage with the rear post stops <NUM>. By maintaining the front portion higher than the rear portion of the cassette <NUM>, contact with other equipment is minimized. The cassette <NUM> should clear any patch cords <NUM> that are connected to other cassettes <NUM> installed in the chassis <NUM> and routed through the cassette tray rail patch cord management loops <NUM>. Once the rear posts <NUM> are seated against the rear post stops <NUM>, the user applies downward pressure to the cassette <NUM> in the region of front posts <NUM>. As downward pressure is applied, the cassette flex beam <NUM> flexes to allow front posts <NUM> to slip past the front lead-in <NUM> of the catch wall <NUM> and into engagement with the catch wall <NUM> of the cassette flex beam <NUM>. The user then may connect patch cords <NUM> and trunk cable furcation legs <NUM> to the cassette <NUM> as necessary as well as route patch cords <NUM> and trunk cable furcation legs <NUM> as described below. Alternatively, a user may connect patch cords <NUM> prior to applying downward pressure to the cassette <NUM> to seat the front posts <NUM>.

A user may also unload cassettes <NUM> from the cassette trays <NUM> of the chassis <NUM> from either the rear or front of the chassis <NUM>. To unload cassettes <NUM> from the rear of the chassis <NUM>, a user first disconnects the patch cords <NUM> from the front of the chassis <NUM>, and then disconnects trunk cable furcation legs <NUM> from the rear of the chassis <NUM>. The user then locates and applies inward pressure to the rear post release latches <NUM> on the cassette <NUM>, for example as shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>. As inward pressure is applied to the rear post release latches <NUM>, the latches <NUM> flex and rear posts <NUM> disengage with the rear post stops <NUM>. As the user continues to apply inward pressure to the rear post release latches <NUM>, the user pulls the cassette <NUM> toward the rear of the chassis <NUM> until the cassette <NUM> clears the chassis <NUM>.

<FIG>, <FIG>, and <FIG> illustrate unloading cassettes <NUM> from the front of chassis <NUM>. To unload cassettes <NUM> from the front of the chassis <NUM>, a user may first position the cassette tray <NUM> in the cassette addition or replacement position as described below. A user then disconnect patch cords <NUM> from the front of the chassis <NUM>. The user may then apply upward pressure on the front portion of cassette <NUM> near the front posts <NUM>, accessing cassette <NUM> through the cassette opening <NUM>. The user applies enough upward pressure on the cassette <NUM> to cause the flex beam <NUM> to flex enough to allow front posts <NUM> to pass by the divot <NUM> of the catch wall <NUM> of the flex beam <NUM>. Once the front posts <NUM> have cleared the front lead-in <NUM> of the catch wall <NUM> of the flex beam <NUM>, the cassette <NUM> is tilted such that the front portion of the cassette <NUM> is higher than the rear portion of the cassette <NUM> as shown in <FIG>. A user may then pull the cassette <NUM> toward the front of the chassis <NUM> until the cassette <NUM> clears the chassis <NUM>, generally maintaining the tilt of cassette <NUM>, as shown in <FIG>. Once the trunk cable furcation legs <NUM> and MPO trunk adapters <NUM> or MPO FAP patch cord adapters <NUM> at the rear of cassette <NUM> are visible, a user may disconnect trunk cable furcation legs <NUM> from the MPO trunk adapters <NUM> or MPO FAP patch cord adapters <NUM> and cassette <NUM>. As shown in <FIG>, a user then preferably removes the cassette <NUM> by positioning the cassette <NUM> such that the rear posts <NUM> are level with front posts <NUM> so that the cassette <NUM> should clear any patch cords <NUM> that are connected to other cassettes <NUM> installed in the chassis <NUM> and routed through the cassette tray rail patch cord management loops <NUM>, as described below.

A user may also replace an LC-MPO cassette <NUM> with an MPO FAP <NUM>. First, a user may follow the procedures for removing a cassette <NUM> above in order to remove the LC-MPO cassette <NUM>. Next the user may connect the trunk cable furcation legs <NUM> to an MPO trunk adapter <NUM>, and insert the new MPO FAP <NUM> following the instructions for installation of a cassette <NUM> from the front of the chassis <NUM> above. If the user desires to add additional trunk cable furcation legs <NUM> to the MPO FAP <NUM> (which allows for up to five additional trunk cable furcation legs <NUM> to attach to five additional MPO trunk adapters <NUM>), the user may route the additional trunk cable furcation legs <NUM> through the rear of the cassette bay <NUM> or <NUM> into the MPO FAP <NUM> from the rear of the chassis <NUM>. As discussed above, for example with reference to <FIG>, MPO FAP <NUM> includes a population feature <NUM> consisting of a plurality of offset rows of population feature pegs <NUM>. After routing the additional trunk cable furcation legs <NUM>, upon which dust caps <NUM> are installed, into the rear of the cassette <NUM>, the user may trap the MPO connectors <NUM> of the trunk cable furcation legs <NUM> between the population feature pegs <NUM>, by inserting the MPO connector <NUM> diagonally through the open path created by the offset rows of the population feature <NUM> and placing the trunk furcation leg <NUM> on the opposite side of the peg <NUM> located at the rear most section of the MPO FAP <NUM> as shown in <FIG>. The population feature pegs <NUM> may therefore temporarily lock the trunk cable furcation legs <NUM> in position, allowing the user to advance the cassette tray <NUM> to the cassette addition or replacement position described below. Because the trunk cable furcation legs <NUM> are locked into the population feature <NUM> of the MPO FAP <NUM>, they are secured from falling out of the rear of the chassis <NUM> and instead are pulled forward along with the MPO FAP <NUM>. Once the cassette <NUM> is in the cassette addition or replacement position the user may reach into the MPO FAP <NUM>, remove the dust caps <NUM>, and attach the additional trunk cable furcation legs <NUM> to any available MPO trunk adapters <NUM>. The user may then add and route any additional patch cords <NUM> as needed, and return the MPO FAP <NUM> to the home position.

As discussed above with reference to <FIG> and <FIG>, for example, the tray guides <NUM>, <NUM>, and <NUM> include three detents, a front detent <NUM>, center detent <NUM>, and rear detent <NUM>. The cassette chassis <NUM> also includes forward limiting flanges <NUM> and rear limiting brackets <NUM>. Each of these features interacts with features of the cassette tray <NUM> to facilitate movement of the cassette tray <NUM> between three different positions-the home position, cord move or change position, and cassette replacement or addition position. In the home position, shown in <FIG>, the protuberance <NUM> of the spring protrusion <NUM> is disposed within the rear detent <NUM>. Additionally, the rearmost portions of the cassette tray rail support ribs <NUM> abut against the rear limiting brackets <NUM>, thereby blocking any further rearward movement of the cassette tray <NUM>.

In the patch cord move add or change position, the protuberance <NUM> of the spring protrusion <NUM> is located within the center detent <NUM>, as shown in <FIG>. In order to advance the cassette tray <NUM> from the home position, a user applies sufficient force toward the front of the chassis <NUM> to cause the spring protrusion <NUM> to flex and allow the protuberance <NUM> to escape from the rear detent <NUM>. The user then continues to apply force toward the front of the chassis <NUM> until the protuberance <NUM> reaches the center detent <NUM>, at which point the protuberance <NUM> interacts with the center detent <NUM>, stopping the forward motion of the cassette tray <NUM>.

If the user wishes to advance the cassette tray <NUM> to the cassette replacement or addition position, the user applies sufficient force toward the front of the chassis <NUM> to cause the spring protrusion <NUM> to flex and allow the protuberance <NUM> to escape from the center detent <NUM>. The user then continues to apply force toward the front of the chassis <NUM> until the protuberance <NUM> reaches the front detent <NUM>. At the same time the protuberance <NUM> reaches the front detent <NUM>, the cassette tray <NUM> also engages with the forward limiting flanges <NUM> to block further forward movement of the cassette tray <NUM>. In order to move the cassette tray <NUM> from the cassette replacement or addition position to either the home or patch cord move add or change positions, a user applies rearward force to the cassette tray <NUM> until the protuberance <NUM> reaches the center detent <NUM> for the patch cord move add or change position or the rear detent <NUM> for the home position.

A user may install a unification clip <NUM> to secure two adjacent cassette trays <NUM> in the same chassis <NUM> together such that they are advanced out of and retracted into the chassis <NUM> at the same time. In order to install the unification clip <NUM>, a user may first advance the cassette trays <NUM> to the patch cord move add or change position, as shown in <FIG>. As shown in <FIG>, a user may then insert the mounting posts <NUM> of the unification clip <NUM> into the unification clip slot <NUM> located on each cassette tray rail <NUM> such that the cable management area <NUM> of the unification clip <NUM> is disposed above and between the front patch cord management loops <NUM> of the cassette trays <NUM> that are being joined together. The user may then apply downward pressure to the unification clip <NUM> to cause the alignment posts <NUM> of the unification clip <NUM> to engage the top of the front-most portion of the cassette tray rails <NUM> or <NUM> to secure the unification clip <NUM> to the cassette trays <NUM> as well as align the cable management area <NUM> of the unification clip <NUM> with the front patch cord management loops <NUM> of the cassette trays <NUM>. The joined cassette trays <NUM> may then be returned to the home position as one unit.

There are two preferred methods of routing patch cables <NUM> as they exit the front of the chassis <NUM>, a split routing scheme method (for example as shown in <FIG> and <FIG>) and a unidirectional routing scheme method (for example as shown in <FIG> and <FIG>). The split routing scheme method may be used when a unification clip <NUM> is not installed. To use the split routing scheme, a user may insert patch cords <NUM> into the front patch cord management loop <NUM> by slipping the cords through the front patch cord management loop slot <NUM>. The patch cords <NUM> attached to the cassette <NUM> installed in the left cassette tray <NUM> are routed through the left-most front patch cord management loop <NUM>, while the patch cords <NUM> attached to the cassette <NUM> installed in the right cassette tray <NUM> are routed through the right-most front patch cord management loop <NUM>. This arrangement allows each cassette tray <NUM> to be moved between the home, cord move or change, and cassette replacement or addition positions without disturbing the patch cords <NUM> attached to the cassettes <NUM> installed in the other cassette tray <NUM> contained in the same row as the moving cassette tray <NUM>.

Claim 1:
A method for loading, from the front, a cassette (<NUM>) into a high density enclosure, comprising:
advancing a cassette tray (<NUM>) to a cassette installation position inside a chassis (<NUM>);
inserting a cassette (<NUM>) into a cassette bay (<NUM>,<NUM>) formed between two rails (<NUM>) disposed on said cassette tray (<NUM>) by placing a rear portion of said cassette (<NUM>) on the tray (<NUM>) so that a respective rear post (<NUM>) of said cassette (<NUM>) is located between a front post stop area (<NUM>) and rear post stop (<NUM>) on each of said rails (<NUM>);
tilting said cassette (<NUM>) slightly upward so that a front portion of said cassette (<NUM>) is higher than said rear portion of said cassette;
pushing said cassette (<NUM>) backward into said cassette bay (<NUM>,<NUM>) while maintaining said tilt of said cassette (<NUM>) until said rear posts of said cassette (<NUM>) engage with and are maintained inside said rear post stops (<NUM>) on said rails (<NUM>); and
applying downward pressure on said front portion of said cassette (<NUM>) until said cassette (<NUM>) is seated in said rail (<NUM>) by interaction of a front post (<NUM>) of said cassette (<NUM>) resting inside said front post stop area (<NUM>).