Editing Hi-Tek Series 725 fourth generation

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[[Hi-Tek|Hi-Tek Corporation]], a division of [[NMB]], produced its [[Hi-Tek Series 725 fourth generation|4th generation]] of [[NMB Hi-Tek keyboards|PC compatible keyboards]] between 1990 and 1998. The 4th generation introduced a flatter case profile.

==Description==
The external appearance of the 4th generation keyboards is flatter than the 3rd generation and is similar to the popular Cherry G8x series of keyboards. The main body of the case is rectangular plank with a wedge extension that places the front face of the keyboard at a slight angle. The front edge of the upper case shell is beveled slightly to provide a more comfortable hand position when resting. A switch accessible through an opening in the rear cover allows the selection from either XT or AT protocols on some models. A set of molded feet can be extended to elevate the back of the keyboard. When collapsed the feet are flush with the bottom surface. Four rubber pads prevent the keyboard from sliding on smooth surfaces.

<gallery widths=250 heights=167>
File:Hi-Tek-118413-002-Top.JPG ‎                             | Top view
File:Hi-Tek-118413-002-Left-Side.JPG ‎                       | Front left view
File:Hi-Tek-118413-002-Right-Side.JPG ‎                      | Right rear view
File:Hi-Tek-118413-002-Rear.JPG ‎                            | Rear view
File:Hi-Tek-118413-002-Status-Led-Panel.JPG ‎                | Lock status led panel
File:Hi-Tek-118413-002-Back.JPG ‎                            | Bottom view
File:Hi-Tek-118413-002-Protocol-Switch.JPG ‎                 | AT/XT protocol switch
File:Hi-Tek-118413-002-Elevation-Foot-Collapsed.JPG ‎        | Elevation foot collapsed
File:Hi-Tek-118413-002-Elevation-Foot-Extended.JPG ‎         | Elevation foot extended 
File:Hi-Tek-118413-002-Rubber-Foot.JPG ‎                     | Rubber non-slip pad
</gallery>

==Construction==
4th generation keyboards use the [[Keyboard_terminology#Discrete_switches|standard method of keyboard construction]] consisting of 4 major components, the upper case shell, the switch assembly, the lower case shell and the cable.

===Upper case shell===
The upper case shell is a single piece of beige, molded plastic with a surface texture created as part of the molding process. The upper case shell incorporates seven un-threaded screw bosses used to secure the lower case shell to the upper case shell using self-tapping screws. Three openings are molded into the shell to allow the status leds to show through the status panel.  The shell is embossed mold date and mold number.  

<gallery widths=250 heights=167>
File:Hi-Tek-118413-002-Case-Shell-Upper.JPG                 | Interior of upper case shell
File:Hi-Tek-118413-002-Status-Led-Openings.JPG ‎             | Upper case shell status led openings
File:Hi-Tek-118413-002-Mold-Date.JPG                        | Upper case shell mold date and number
</gallery>

===Lower case shell===
The lower case shell is molded from the same plastic as the upper case shell. The lower case shell incorporates six un-threaded screw bosses used to secure the switch assembly to the lower case shell using self-tapping screws. Interestingly, most examples only use one screw. The cable opening is shaped to engage and molded portion of the cable to provide retention and strain relief. A pair of feet are separately molded and snap into recesses in the rear cover. The position feet lie flush with surface of the rear cover when retracted and lock into place when extended. The shell has an embossed mold date and mold number. A set of four tabs are used in some examples to retain a small controller PCB.

<gallery widths=250 heights=167>
File:Hi-Tek-118413-002-Lower-Case-Shell.JPG ‎                | Lower case shell
File:Hi-Tek-118413-002-Lower-Shell-Cable-Retention.JPG      | Lower case shell cable opening
File:Hi-Tek-118413-002-Lower-Shell-Cable-Retention-2.JPG   ‎ | Lower case shell cable showing retention
File:Hi-Tek-118413-002-Retention-Taps.JPG                   | Lower case shell board retention tabs
</gallery>

====Labels====  
All 4th generation keyboards have an identification label that lists FCCID, country of origin, manufacturer name and address, certifications, part number, and revision. The identification label has a box for serial number if a separate serial number label is not used. All NMB Hi-Tek keyboards were "MADE IN THAILAND". Up to 3 small, colored paper inspection stickers can be found near the upper left hand corner of the smooth label section on the exterior. 

===Cable===
4th generation keyboards came with a variety of cables. Early examples have thick coiled cables with 5 pin DIN connectors similar to those of 3rd generation keyboards. Some have a thinner coiled cable with either a 5 pin DIN connector or 6 pin mini DIN PS/2 connector. Later keyboard come with a straight cable with either a 5 pin DIN connector or 6 pin mini DIN PS/2 connector.

===Switch assembly===
The switch assembly consists of one or two PCBs, switches, key caps and switch plate. The switch plate is constructed of stamped steel with a thin, black finish. The ends of the plate are bent to mount to the upper case using 1 screw per side. The switches are [[Hi-Tek Series 725| Series 725]]. Two different PCB configurations are known to exist. Most examples have a single PCB with no anti-ghosting diodes. Some early models have a second small PCB which contains the controller and clips into a set of four retention tabs in the lower case shell. The main PCB on these examples has anti-ghosting diodes and supports N-key rollover. 

===Keycaps===
The keycaps are made of PBT with high quality dye-sublimated legends. They have cylindrical tops and sculpted profile. The legends on later examples is thinner than early examples. Some examples have the stepped keycaps found on all 3rd generation boards.

==Known part numbers ==
<div style="margin-left: 0.5em;">
{| class="wikitable"
! Part Number
! Rev
! Model
! Date
! Main Switch
! Spacebar Switch
! LED Switch
! Cable
! FCCID
! Branding
! Reference
|-
|[[Hi-Tek 118413-002|118413-002]]
|
|RT 101+INTEL
|05-92
|Grey 2-Eye Tactile
|Grey 2-Eye Tactile
|Grey 2-Eye Tactile
|Beige coiled with PS/2 connector
|AQ65RT101-LC
|None
|
|-
|[[Hi-Tek 116300-004|116300-004]]
|
|RT-102 IT
|04-90
|Black 2-Eye Tactile
|Neon Green 2-Eye Tactile
|Black 2-Eye Tactile
|Beige coiled with AT connector
|AQ659ZRT-725M
|None
|
|-
|Hi-Tek 120016-201 REV.B
|
|[[NMB RT-8255C+|RT-8255C+]]
|06-95
|Black 2-Eye Clicky
|Blue 2-Eye Spacebar Clicky
|No Integrated LED
|Beige coiled with AT connector
|AQ6-OAKZ15
|None
|}
</div>

[[Category:Hi-Tek keyboards]]
[[Category:NMB keyboards]]