Test access apparatus

Portable test apparatus utilized to access a field of test points comprises either a single access tool (100) or a multiple access adaptor (200) depending on the mode of testing required. Tool (100) is usually employed for accessing the field to effect a periodic testing whereas adaptor (200) is generally used for planned test activities. Tool (100) comprises body (111), guide assembly (150) and cover plater (170) which house clamp assembly (130) and pin contact assembly (180). Clamp assembly (130) operates in scissor-like fashion for engaging and disengaging tool (100) from test field grips (401). Spring-loaded pins (181) penetrate apertures (403) within the test field to contact the test points. Adaptor (200) comprises body (211), center panel (240) and guide (260) which enclose pin contact assembly (280); in addition, cam-lever drive assembly (210) attached to body (211). Drive assembly (210) has means for grasping a frame (50) associated with the test field so as to draw body (211) towards frame (50). In the engaged position, spring-loaded pins (281) contact the test point. Recesses (266) in the front face of guide (260) align juxtaposed test field grips to establish a uniform field of test points.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates generally to electrical connectors and, more 
particularly, to portable apparatus that is adapted to access a field of 
test points for electrical testing. 
2. Description of the Prior Art 
Telecommunication switching systems operate on the basic principle of 
terminating numerous transmission facilities at a central location and 
then subsequently interconnecting, when required, selected pairs of 
facilities through a comprehensive switched network. In a telephone 
central office, a component of this comprehensive network is the main 
distribution frame which terminates outside plant facilitates and, 
moreover, furnishes a nonswitched interconnection juncture for joining 
central office equipment to the outside plant facilities. 
The outside facilities homing on the central office are usually subjected 
to periodic tests, but aperiodic tests may also be required, particularly 
during troubleshooting activities for fault conditions on the facilities. 
In either mode, to provide efficient and reliable access for testing, main 
frame systems oftentimes incorporate fields of test points which are 
typically bridged electrically to the outside facilities terminated on the 
main frame. Due to the two different modes of testing, it is desirable to 
either (1) be able to make connections to a larger number of test points 
at once and to interconnect various types of test equipment, or (2) effect 
rapid, one-at-a-time connection to a particular test point and 
interconnect a variety of test instruments. 
Numerous methods and devices are known in the prior art for making 
temporary connections to test points. These devices range: from the 
rudimentary type wherein a lead is soldered or an alligator-type clip is 
clamped to a test point; to the most complex type wherein a plurality of 
grip-like fingers are ganged to operate in unison via cam-lever means or a 
spring-loaded pin arrangement mounted with thumb screws is employed to 
contact many test points at once. 
Two references exemplifying test connectors of the latter type are given in 
U.S. Pat. Nos. 3,275,971 and 3,509,297, both issued to J. H. King on 
September 27, 1966 and Apr. 28, 1970, respectively. These two test 
connectors are designed for use on conventional main frame systems that 
employ spring-like clamps as part of the interconnection arrangement. 
Conductive fingers provide electrical test access by contacting the 
appropriate clamps when the test apparatus is in place on the frame. 
Turndown screws facilitate frame mounting in '297 whereas in '971 the 
fingers form the primary support for frame mounting. 
Presently available prior art frame access devices have been designed for 
conventional main frame systems. In these systems, besides the 
interconnection and test fields already described, a third field provides 
protection provisioning to safeguard personnel and equipment against 
excessive voltage and current. In a functional sense, the frame system 
provides for connection, testing and protection; and physically, in 
conventional frame systems, separate apparatus have served each function. 
However, as elaborated upon later, the subject matter of the instant 
application, as well as three copending applications field on even date 
herewith, discloses a new modular main frame system which eliminates the 
independent appearance of the test field. The conventional, stand-alone 
test field appearance made inefficient use of available space within the 
central office and therefore became amenable for modification. 
One component of the newly devised system is the protection device. This 
device, besides providing the required protection against overvoltage and 
overcurrent conditions, is also adapted to provide the electrical test 
field. Test lands, internal to the protection device, electrically contact 
the outside plant pairs and these lands are accessible through apertures 
in the protector housing. In support of the new frame arrangement, test 
access apparatus of an unconventional design are now required. Rather than 
accessing fields serving only a single purpose and best described as 
lug-type, clamp-like, plug- and jack-type, and so on, the apparatus must 
access equipment serving multipurposes. The test apparatus must be adapted 
to conform with the internal layout of the protector device, particularly 
the positioning of the flat test lands, as well as the physical dimensions 
and characteristics of the protector, particularly a protruding, finger 
grip on the housing which facilitiates handling. 
SUMMARY OF THE INVENTION 
The foregoing requirements are effected with the present invention of main 
frame test apparatus which access a test field formed from a plurality of 
juxtaposed devices and which provide electrical interconnection between a 
plurality of test points accessible through apertures in the devices and a 
test station having suitable test instruments. 
The test apparatus in accordance with the present invention generally 
comprises: a body having a plurality of channels arranged in mirror-image 
relation to the apertures in the test field; electrically conductive probe 
means, arranged in the channels, for penetrating the apertures and 
contacting the test points; means for centering and holding the body in 
fixed relation proximate to the test field apertures to insure complete 
penetration of the probe means; and means for electrically joining the 
probe means to the test station. 
In one illustrative embodiment of the present invention, the apparatus 
comprises a single access tool that provides one-at-a-time access to a 
protector device for contacting the flat test lands accessible through 
apertures in the protector housing. Two spring-loaded electrically 
conductive pins are mounted in two channels in the body. The movable end 
of the pin emanates from the body whereas the spring-end is contained 
within the body. The pins are urged into the apertures to contact the test 
lands with sufficient pressure to penetrate deleterious nonconductive 
coatings. The tool grasps the finger grip of the housing with clamps 
having hooked ends and which are operated in scissor-like fashion for 
engaging and disengaging the grip. 
In a second illustrative embodiment of the present invention, the apparatus 
comprises a multiple access adaptor which provides a multiplicity of 
connections to contiguous protector devices. A matrix-like grid of 
spring-loaded pin pairs mount in a body that includes a front alignment 
face and a back drive assembly. The pins are positioned in front face 
channels to penetrate and exert pressure in a manner similar to the single 
access test tool. Moreover, the front face has a plurality of recesses 
arranged in mirror-image relation to the field of finger grips so as to 
align the devices for accessing. The adaptor has means for grasping the 
main frame and a cam-lever arrangement coupled to a back drive plate draws 
the adaptor towards the frame to drive the pins into the test apertures. 
The electrical test access apparatus disclosed herein is part of a newly 
devised modular main frame system which eliminates the independent 
appearance of the test field by incorporating test access within the 
protector device and, in addition, facilitates installation and 
maintenance of the modular components using plug-in and snap-in details. 
One protector device which combines the protection as well as testing 
function into a single safety module is the subject matter of U.S. patent 
application Ser. No. 78,961, filed on even date herewith by A. R. 
Montalto, L. J. Scerbo and J. P. Starace. Another protector device serving 
the protection and testing functions is the subject matter of U.S. patent 
application Ser. No. 79,064, filed on even date herewith by R. M. Bulley 
(Case 1). Central office apparatus which utilizes the protector devices 
and the instant test access apparatus is the subject matter of U.S. patent 
application Serial No. 79,063, filed on even date herewith by P. R. 
Briggs, Jr. and L. J. Scerbo. 
One feature of the test apparatus implemented in accordance with the 
present invention is the advantageous use of the projecting finger grip 
which, normally, merely facilitates manual handling. The single access 
tool employs the grip as the sole means of maintaining drive force to the 
spring-loaded pins. The multiple access adaptor uses the juxtaposed 
arrangement of the grips to establish a uniform field of test points by 
aligning the grips with the matrix-like grid of recesses in the adaptor's 
front face. Moreover, as the test adaptor is placed over the protectors, 
the test pins span the grips and align the individual protectors. 
Another feature of the adaptor is its utility in providing a bridging 
interconnection between not only a test station and the main frame but 
also between the main frame and a station comprising appearances of other 
outside plant facilities. Such a situation exists during a cable cut-over 
wherein both old and new cables must be bridged between their respective 
main frame appearances prior to the cut-over from old to new facilities. 
Two adaptors with apparatus for mating the adaptors provide this 
capability. 
Other features and advantages of the present invention will be apparent 
hereinafter from a detailed description of the invention and the appended 
claims taken in conjunction with the attached drawing of alternative 
illustrative embodiments.

DETAILED DESCRIPTION 
1. Single Access Tool 
The specific example of the one-at-a-time test access apparatus described 
by way of illustration is shown in exploded perspective view in FIG. 1 
and, as assembled, ready for engagement to a protector device, in FIG. 2. 
With reference to FIG. 1, the overall tool 100 is generally characterized 
by five component parts, namely: bottom plate 110; clamp assembly 130; 
guide plate 150; spring contact pins 180; and cover plate 170. The 
structure as well as operation of tool 100 will be set forth in the 
description that follows. 
The bottom plate 110 includes a thin, rectangularly-shaped body portion 111 
and, formed integrally therewith at the back end of body 111, a winged 
portion 112 of the same thickness. Extending along the longer dimensional 
sides of body 111 are left and right sides walls 113 and 114, 
respectively, which project above the top surface of body 111 a distance 
approximately equal to the body thickness. The planes containing the inner 
surfaces of walls 113 and 114 are generally transverse to the top surface 
117 of body 111. A portion of the front edge of body 111 is recessed to 
form substantially square-shaped notch 115, which has an opening of about 
one-third of the width of body 111 and is centered on the front edge. 
Extending along the front face of body 111, between left side wall 113 and 
notch 115, is left tip wall 118 which is of the same height as wall 113. 
Similarly shaped right tip wall 119 is formed between notch 115 and right 
side wall 114. The plane containing the front surfaces of tip walls 118 
and 119 is transverse to the planes containing the front surfaces of walls 
113 and 114 and the plane of top surface 117. Located on top surface 117 
and adjacent the recessed edge of notch 115 is square spacer 116, which 
rises above surface 117 the same distance as the side walls and the tip 
walls. Also located on top surface 117 near the rearward portion of body 
111 and equidistant from side walls 113 and 114 is circular hub 120. The 
diameter of hub 120 is approximately the same as the dimension of one side 
of spacer 116 and the heights of hub 120 and spacer 116 are substantially 
the same. Winged-shaped portion 112 is formed from two symmetrical, 
semicircular recesses 121 proximate to the rearward portion of bottom 
plate 110. The radius of each recess 121 is about 30 percent of the width 
of body 111. Extending along the back edge of member 112 is back wall 122, 
which abuts the semicircular recesses 121 near their ends and which is the 
same height as side walls 113 and 114. The front surface of back wall 122 
lies in a plane generally parallel to the plane containing the front faces 
of tips 118 and 119. It is contemplated that bottom plate 110 may, for 
example, be formed as a single unit from a high impact, fire retardant, 
thermoplastic resin through an operation such as injection molding. 
The clamp assembly is composed of left clamp 131 and companion right clamp 
132 both similarly designed and constructed from substantially the same 
material, preferably metal. Near the terminal ends of clamps 131 and 132 
are respectively inwardly disposed hooks 133 and 134 that cooperate to 
form means for grasping finger grip 401 (see FIG. 2) so as to engage and 
hold tool 100 in a fixed relation to protector device 400 (see FIG. 2). 
Blade 131 has arch-like protuberance 135 projecting inwardly at a point 
intermediate its length. Similarly shaped proturberance 136 emanates 
inwardly from clamp 132. The top surface of protuberance 135 is cut away 
to form landing 137, whereas the underside of proturberance 136 is removed 
to mate with landing 137 (not visibly apparent in the Figures). Dowel-like 
rod 123, which is formed integrally as part of body 111, penetrates 
aperture 138 in protuberance 136 and a correspondingly vertically aligned 
aperture (not shown) in landing 137 to form a pivot point about which 
clamps 131 and 132 are rotatable. When proturberances 135 and 136 are 
superimposed, landing 137 cooperatively meshes with the underside of 
protuberance 136 so that clamps 131 and 132 are operable in scissor-like 
fashion. 
From the rearward ends of clamp 131, upper and lower left lips 139 and 140, 
respectively, project inwardly towards clamp 132 and these lips are 
separated to define gap 142 between them. Similarly shaped and arranged on 
clamp 132 is an upper right lip 141 and a lower right lip (not apparent in 
FIG. 1) project towards clamp 131. V-shaped spring 143 has diverging free 
ends 144 and a coil 145 at the spring vertex. Spring 143 is preferably 
formed from a unitary piece of resilient material. One spring end 144 
slips into gap 142, whereas the other end 144 slips into the gap under lip 
141. When assembled, spring 143 is aligned and held in place by coil 145 
straddling hub 120 which serves as a pivot point and fixes the position of 
spring 143. Spring 143 exerts outward forces to the clamp ends proximate 
lips 139 and 141 to cause hooked ends 133 and 134 to grasp grip 401 (see 
FIG. 2) when it is inserted in notch 115. The inner surfaces of the clamps 
proximate hooked ends 133 and 134 straddle spacer 116 whenever pressure P, 
exerted on the clamp ends to counteract spring force for engaging and 
disengaging, is removed. 
Guide assembly 150 includes a thin, rectangularly-shaped alignment plate 
151 and winged-shaped support 152 formed integrally with plate 151 at its 
back edge. A portion of front edge 153 of plate 151 is recessed to form 
rectangularly-shaped indent 154, which is vertically aligned and congruent 
with the opening formed by notch 115 and the space between tip walls 118 
and 119. Two laterally disposed, symmetrically located semicircular 
channels 155 are formed in top surface 156. The distance between the 
center lines of the channels is substantially the same as the distance 
between the two apertures 403 to be accessed in housing 401 (see FIG. 2). 
Each channel 155 extend into plate 151 a distance of about 40 percent of 
the length of plate 151. Centered on and abutting the rearward end of 
channel 155 and extending for about 40 percent of the length of plate 151 
is laterally disposed semicircular groove 157 formed in top surface 156. 
The diameter of groove 157 is larger than the diameter of channel 155 so 
seat 158 is formed at their juncture. Conically-shaped, laterally disposed 
taper 159, centered on and adjacent the rearward end of each groove 157, 
extends the remaining approximately 20 percent length of plate 151 and 
exits at its back edge 160. Semicircular nub 161 protrudes from back edge 
160 at about its midpoint. When the tool is assembled, nub 161 rests on 
the top surface of hub 120 to preclude vertical movement of spring 143. 
Winged support 152 is formed from two symmetrical, dome-shaped recesses 162 
proximate the rearward portion of guide assembly 150; recesses 162 form 
finger stops that aid in equalizing pressure P applied to individual 
clamps 131 and 132. Each dome recess 162 is vertically aligned and 
congruent with the corresponding semicircular recess 121 in plate 110. A 
portion of top surface 163 of support 152 is recessed along its back edge 
to form landing 164. Raised, semicircular guide 165 is disposed in 
front-to-back relation on landing 164 at its midpoint and provides strain 
relief for leads 186. Landing 164, domed recesses 162, back edge 160 and 
nub 161 cooperate to form Y-shaped recess 166 which accommodates internal 
electrical connection of leads 186 from springs 183 to the external test 
station (not shown). 
The perimetrical shape of guide plate 150, as seen in top elevational view 
looking towards top surface 156, is congruent to the perimetrical shape of 
bottom plate 110 as viewed in top elevation towards top surface 117. 
Similarly, cover plate 170 has the same outline shape as guide plate 150 
and bottom plate 110 as viewed in top elevation towards top surface 117. 
Both guide plate 150 and cover plate 170 are formed from an insulative 
material similar to that selected for bottom plate 110. As formed, the 
underside of cover 170 has correspondingly arranged channels 172 which 
mate with channels 155 as well as grooves and tapers (not shown) which 
mate with grooves 157 and tapers 159, respectively. 
Inserted within the hollow formed by overlayed and abutting channels 155 
and 172 are metallic pins 181, each having a pointed end 185 protruding 
through front face 153. The other end of each pin 181 is affixed to 
metallic stop 182, which is free to move to and fro within semicircular 
groove 157 and the companion groove in plate 170. Seat 158 constrains 
lateral movement of stop 182 on one end of its excursion. Electrically 
joined to each stop 182 is the front end of coil spring 183, which extends 
rearwardly so that tapered spring end 184 seats in taper 159 and the 
associated taper in plate 170. Pins 181 are slidable within channels 155 
and 172 so that as pointed ends 185 contact, for example, flat test lands 
(not shown) within device 400 as tool 100 is urged towards device 400 (see 
FIG. 2), pins 181 are driven into a retracted position within tool 100. As 
pins 181 retract, springs 183 exert a force proportional to displacement 
so that points 185 penetrate any nonconductive coatings on test lands. 
A two-wire cord having leads 186, routed across landing 164 so that guide 
165 separates each wire, attaches to spring tapers 184. Two separate 
electrical access paths between the test lands and test instruments (not 
shown) are provided through leads 186, springs 183, stops 182 and pins 
181. 
Assembly is completed by juxtaposing the five component assemblies depicted 
in FIG. 1. When assembled, clamp assembly 130 rests on top surface 117 and 
is housed within an exterior shell comprising side walls 113 and 114, tip 
walls 118 and 119 and back wall 122. Thus, clamp assembly 130 lies between 
the plane containing surface 117 and the plane which contains the top 
surfaces of: walls 113, 114, 118, 119 and 122; spacer 116; and hub 120. 
Dowel 123 penetrates aperture 138 in clamp assembly 130 and seats in 
vertically aligned aperture 167 in alignment plate 150. Screw 175, which 
penetrates apertures 173 and 168 and seats in threaded aperture 124 in 
spacer 116, as well as screws 176, which penetrate apertures 174 and 169 
and seat in threaded apertures 125, complete the assembled tool 100. 
2. Multiple Access Adaptor 
The specific example of a multiple access test adaptor described by way of 
illustration is shown in exploded perspective view in FIG. 3, except for 
the spring-loaded contact pins which are depicted in the exploded side 
view of FIG. 4. 
With referencre particularly to FIG. 3, test adaptor 200, shown in its 
locked position, is generally characterized by four component parts, 
namely: drive assembly 210, center panel 240, front guide 260 and contact 
pin assembly 280 (see FIG. 4). The structure as well as the operation of 
tool 200 are elucidated in the following description. 
The drive assembly 210 comprises insulative, rectangularly-shaped body 211 
and cam-lever assembly 220 mounted on body 211. Rightside wall 212, back 
wall 213, top wall 214, as well as the left and bottom walls (not visibly 
apparent in the Figures), combine to form recess 215 in the back surface 
of body 211 (see FIG. 4). The purpose of recess 215 will be described 
shortly. 
Cam-lever assembly 220 includes: rectangularly-shaped main support member 
221 disposed in parallel relation to back wall 213 and extending slightly 
beyond right side wall 212 and similarly on the left side, member 221 
being slidably coupled to body 211 with spring-loaded, elongated fasteners 
222; and arms 224, formed integrally with support member 221 and oriented 
in a forwardly directed, perpendicular fashion to member 221 at its ends. 
Arms 224 have spaced-apart hooks 225 and 226 formed on the underside of 
each arm. Either hook 225 or 226 couples to a correspondingly aligned lug 
51 mounted on the main distribution frame vertical support 50. Lug 51 
provides a fixed grip means for drawing test adaptor 200 into firm contact 
with the test point field. The frontmost hook 225 is utilized for 
accessing frame apparatus having protector devices 400 inserted therein, 
whereas the rearmost hook 226 is used to directly access the sockets 404 
employed to seat protection devices whenever the protector devices are 
removed. Each fastener 222 has axial spring 2222 encircling fastener 222 
and has enlarged head 227 that precludes fastener 222 from slipping 
through apertures 223 in body 211. However, the diameter of each aperture 
223 relative to the elongated portion of each fastener 222 allows for 
vertical and horizontal movement of members 221 relative to body 211 to 
facilitate alignment of arms 224 with lugs 51. 
Attached to the back wall of member 221 is a pair of identical, 
symmetrically located, generally U-shaped brackets 229. Right and left 
bracket side walls 230 and 231 lie in parallel planes that are 
perpendicular to the plane containing member 221. Each side wall, 230 and 
231, has a transverse aperture 232 for accepting pivot-like pins 233. Each 
pin 233 forms a pivot point about which eccentric cam 234 is rotatable. 
The driving force to rotate each cam 234 is provided by lever 235 
emanating from each cam lobe. Levers 235 are driven in unison with handle 
236, which couples to the top portion of each lever 235. As handle 236 is 
rotated from its bottommost position, cam 234 engages drive plate 237, 
which is suitably mounted on rear wall 213 of body 211. Continued rotation 
of handle 236 causes forward displacement of body 211 (as well as panel 
240 and guide 260), relative to drive assembly 220 due to increasing cam 
diameter and forward motion along fasteners 222. When handle 236 is in its 
uppermost position, maximum separation between body 211 and assembly 220 
is achieved. Since arms 224 maintain a fixed relation to the main frame, 
the cam operation drives body 211 towards the frame and ultimately 
provides suitable penetration force to contact pin assembly 280. 
Hand-grip 239, affixed to member 221 at about its midpoint with the aid of 
stanchion 238, facilitates manipulation and alignment of tool 200 during 
its use. 
Thin, rectangularly-shaped, insulative center panel 240 has groups of 
apertures laterally disposed between its front face 241 (see FIG. 4) and 
back face 242. Each group comprises two vertically aligned apertures. The 
row of aperture pairs adjacent top edge 243 is designated 301 to 310, the 
row below this 311 to 320, and so forth. Using group 301 as exemplary, the 
top aperture has indicia 301a and the other aperture is designated 301b. 
All apertures are tapered, with the narrow opening of the taper exiting 
through back face 242. 
Insulative front guide 260 is of essentially the same perimetrical shape as 
panel 240 and it has groups of channels laterally disposed between its 
front face 261 (see FIG. 4) and back face 262. The channels on back face 
262 are arranged and axially aligned in mirror-image relation to the 
apertures exiting front face 241. Accordingly, the channels in the row 
nearest edge 263 are designated 401 to 410, the adjacent row 411 to 420, 
and so forth. Referring particularly to FIG. 4, all channels are 
bidiametrical. Using channel group 410 as exemplary, with the top channel 
being designated 410a, the larger diameter channel portion 410a1 
penetrates guide 260 to about one-half its thickness. The smaller diameter 
portion 410a2 penetrates the remaining thickness and exits front face 261. 
The spacing of the channels in front face 261 is in mirror-image relation 
to the field of test points to be accessed by tool 200. Elongated, 
vertically disposed grooves 267 reduce the overall weight of adaptor 200. 
Contact pin assembly 280, interposed between panel 240 and guide 260, 
comprises metallic pins 281, each having a rod-like body 282 with taper 
283 on one end and cylindrical seat 284 on the other end. Due to the 
diameter of each seat 284, it is free to move to and fro in the larger 
diameter channel portion 410a1, but not in the smaller diameter portion 
410a2. Rod 282 is slidable within both channel portions and taper 283 
protrudes through front face 261. The driving force for each pin 281 is 
provided by a spring 285, which is affixed to seat 284 on one end and has 
taper 286 on the other end. Taper spring end 286 is suitably proportioned 
to seat in the tapered portion of aperture 310a, with the narrow end of 
taper 286 protruding slightly from back face 242. Since test adaptor 200 
is used to access a test point field comprising either flat test lands or 
tapered socket openings, pin 281 is adapted for use in either mode by 
providing lip 287 at the juncture of taper 283 and rod 282. Lip 287, 
formed by rod 282 having a slightly larger diameter than taper 282 has at 
its largest diameter, does not allow complete penetration of rod 282 into 
the socket openings. 
Mechanical assembly is completed by juxtaposing the four component 
assemblies depicted in FIG. 4. With reference to FIG. 3, top and bottom 
edge notches 217 from assembly 210 fit into correspondingly aligned 
polarizing grooves 245 of center plate 240. In addition, corner polarizing 
ledge 265 and perimetrical lip 268 from front guide 260 seat in a 
complementarily arranged protuberance (not visibly apparent) and recess 
246, respectively, in front face 241. Fasteners 218, which penetrate holes 
244 in panel 240, seat in threaded apertures 264 in guide 260 to complete 
the assembled tool. 
In the assembled unit, spring taper ends 286 protrude into recess 215. 
Wiring from cables 291, comprising 100 wire pairs, enter tool 200 through 
the bottom, rear portion of body 211 via insulative coupler 293 of cover 
292 and terminate, one wire per pin, on contact pin assembly 280. 
Referring particularly to FIG. 5, which depicts a frontal view of face 261, 
oval-shaped grip alignment recesses 266 are shown between pairs of channel 
openings. When test adaptor 200 is manipulated to access a juxtaposed 
arrangement of protector devices, pairs of pins 281 (see FIG. 4) initiate 
alignment of each protector device by straddling the individual 
oval-shaped finger grip on the device. Completed alignment is achieved 
when the grips are urged by the side walls of recesses 266 into a uniform 
field as drive assembly 210 is operated to draw adaptor 200 towards the 
main frame. 
Although the foregoing description has focused on the use of adaptor 200 
for accessing the outside plant facilities, via either test lands or 
sockets, adaptor 200 may also be conveniently utilized for accessing 
central office equipment through sockets 405. With devices 400 removed 
from frame 50, adaptor 200 merely need be rotated 180 degrees to an 
inverted orientation; arms 224, via hooks 226, grip lugs 51 and adaptor 
200, are operated in a manner essentially the same as that described for 
the noninverted orientation of FIG. 3. Since pin polarity is also reversed 
in this mode, suitable equipment, such as an adaptor cord, repolarizes the 
connection. 
It is to be further understood that the test access apparatus described 
herein is not limited to the specific forms disclosed by way of example of 
illustration, but may assume other forms, materials or dimensions limited 
only by the scope of the appended claims.