embodiments of the present invention are described below by referring to fig1 - 15 of the accompanying drawings . an embodiment is illustrated in fig1 where the present invention is applied to a connector 20 for electrically connecting a printed circuit board 10 and a memory card 11 . the printed circuit board 10 comprises an insulating board on which wiring is printed to form multiple interconnects . the memory card 11 is a rectangular card incorporating an ic memory . ribs 12 are formed on both side surfaces of the card to prevent misinsertion . one side surface of the memory card 11 is provided with a recess 13 for locking purposes . a switch 14 for inhibiting writing is slidably formed on the other side surface . a cutout 15 ( fig2 ) is formed at one corner of the front end of the memory card to judge whether the insertion is incorrect or not . furthermore , the memory card 11 has a plurality of juxtaposed input / output connection portions or interconnects 16 on its bottom surface ( fig3 ). the connector 20 is so designed that a slider 40 is squeezed from above and below by a top shell 21 and a flat , gatelike connector body 36 , as shown in fig2 . the slider 40 is slidably mounted to one arm 31 of the connector body 30 . the top shell 21 has been stamped from a metal sheet and pressed . resilient pawls 22 and 23 are carved out from near both ends of the top shell 21 . a resilient pawl 24 is carved out from one corner to prevent a lever 51 ( described later ) from floating . in the present embodiment , the connector is surface - mounted on the printed circuit board . where connection with a flexible printed circuit ( fpc ), for example , is made , the connector body 30 may be squeezed from above and below by the top shell 21 and a bottom shell ( not shown ), and a connector for the fpc may be mounted to the connection end surface . as shown in fig8 the top end of the connector body 30 is provided with plural terminal holes 30 a formed at a given pitch . connector terminals 50 are pressed into the terminal holes 30 a from the outside . as shown in fig4 a support hole 33 ( described later ) is formed in the top end surface of the arm 31 of the arms 31 and 32 of the connector body 30 , the hole 33 forming a pivot for rotation of the lever 51 . a projection 34 for guiding the slider 40 ( described later ) is formed near the hole 33 . a tapering guide groove 35 is formed near one end of the projection 34 . a slit 36 for accommodating a coil spring 52 ( described later ) is formed near one end of the guide groove 35 . a support protrusion 36 a that supports the coil spring 52 protrudes into the slit 36 . a terminal hole 37 is formed in the base portion of the other arm 32 of the connector body 30 . the bottom surface of a connection portion 53 a of a fixed contact terminal 53 mounted to the connector body 30 is exposed from the terminal hole 37 so as to be connectable . a first movable contact member 54 and a second movable contact member 55 are mounted near one end of the connector body 30 . the fixed contact terminal 53 , first movable contact terminal 54 , and second movable contact terminal 55 together form a switch used to judge whether the memory card 14 has been set to inhibit writing . as shown in fig7 a movable contact portion 54 a and a pressure contact portion 54 b which make contact with the fixed contact terminal 53 are formed on the first movable contact terminal 54 by stamping and bending a conductive spring member . similarly , a movable contact portion 55 a and a pressure contact portion 55 b which make contact with the movable contact terminal 54 are formed on the second movable contact terminal 55 by stamping and bending a conductive spring member . in fig1 and 13 , indicated by 55 c is an insulating spacer . as shown in fig5 the aforementioned slider 40 is a molded plastic product having a cross - sectional shape capable of slidably fitting over the guide projection 34 of one arm 31 of the connector body 30 . a substantially heart - shaped cam groove 41 for forming an alternate mechanism is formed at one end of the top surface of the slider 40 . as shown in fig5 a , this cam groove 41 has a first support point 41 a at which an operation is started , a second support point 41 b at which one end 51 b of the lever 51 moved away from the first support point 41 a falls , a third support point 41 c at which one end 51 b of the lever 51 moved away from the second support point 41 b falls and settles itself , and a fourth support point 41 d at which one end 51 b of the lever 51 moved away from the third support point 41 c falls . a slide groove 42 engaged by a guide pin 57 is formed in the center of the slider 40 , the pin 57 being mounted on a locking pawl 56 ( described later ). a support protrusion 43 that supports a coil spring 58 is formed at the other end of the slider 40 . the coil spring 58 biases the locking pawl 56 inward . as shown in fig5 b and 5c , a recess 44 for receiving the coil spring 52 is formed at one end of the bottom surface of the slider 40 . protrusions 45 a and 45 b having the same height protrude from the bottom surface of the slider 40 to prevent the slider 40 itself from tilting . as shown in fig8 the coil spring 52 is fitted over the support protrusion 36 a of the connector body 30 . then , the coil spring 58 is mounted to the support protrusion 43 of the slider 40 . the guide pin 57 is mounted with a press fit in a hole 56 a extending through the locking pawl 56 . the guide pin 57 is fitted into the slide groove 42 in the slider 40 . one end of the coil spring 58 is mounted in an insertion port 56 b formed in the locking pawl 56 , whereby the locking pawl 56 is biased inward . then , the slider 40 is slidably mounted on the protrusion 34 on the connector body 30 . at this time , the guide pin 57 is engaged in the guide groove 35 . one end 51 a of the substantially u - shaped lever 51 is inserted into the support hole 33 in the connector body 30 . the other end 51 b is anchored to the first support point 41 a in the heart - shaped cam groove 41 . the top shell 21 is mounted to the connector body 30 and they are assembled as a unit . at this time , the resilient pawl 24 on the top shell 21 is pressed against the lever 51 to limit the position . in this way , disengagement is prevented . the locking pawl 56 is biased inward by the spring force of the coil spring 58 as shown in fig1 . therefore , when the slider 40 slides into a deeper position , the guide pin 57 moves along the tapering guide groove 35 . as the slider 40 goes deeper , the locking pawl 56 protrudes inward along the slide groove 42 and engages the locking recess 13 in the memory card 11 . the operation performed when the memory card 11 is inserted into the connector 20 composed of the aforementioned components is next described . before the memory card 11 is inserted , the slider 40 is located near the opening in the connector 20 . the other end 51 b of the lever 51 is located at the first support point 41 a in the cam groove 41 . the guide pin 57 is located ahead of the guide groove 35 . when the memory card 11 is inserted from the opening in the connector 20 , the memory card 11 fits over the slider 40 . the resilient pawls 22 and 23 on the top shell 21 push the card 11 against the connector body 30 . if the memory card 11 is pushed in further , the slider 40 slides against the spring force of the coil spring 52 . concomitantly with this movement , the other end 51 b of the lever 51 moves from the first support point 41 a to the second support point 41 b . also , the guide pin 57 moves along the guide groove 35 . therefore , the locking pawl 56 biased inward rotates and is pushed forward into the locking recess 13 ( fig1 b and 10c ) in the memory card 11 , thus preventing the pawl from coming off . at the same time , the input / output interconnects 16 of the memory card 11 come into contact with their respective connector terminals 50 . in the present embodiment , where the insertion of the memory card 11 is done from the wrong side , the cutout 15 bears against the slider 40 to thereby prevent wrong insertion . where the inserted memory card 11 is turned upside down , the misinsertion preventive ribs 12 formed on both side surfaces of the connector body 30 bear against the edges of the opening in the arms 31 and 32 of the connector body 30 . this creates the advantage that misinsertion is prevented with certainty . when pushing of the memory card 11 is released , the spring force of the coil spring 58 pushes back the slider 40 . however , the other end 51 b of the lever 51 falls into the third support point 41 c from the second support point 41 b ( fig1 d ), thus hindering return of the slider 40 . therefore , the locking pawl 56 remains engaged in the locking recess 13 . the memory card 11 is locked . there is no fear of the card coming off . at this time , the locking pawl 56 is merely biased by the spring force of the coil spring 58 and so if the memory card 11 is forcibly pulled out , the locking pawl 56 is pushed back . there is no fear of the pawl becoming damaged . as shown in fig1 , where the memory card 11 is mounted within the connector 20 , the card 11 bears against the pressure contact portion 55 b of the second movable contact terminal 55 , and the movable contact portion 55 a comes into contact with the first movable contact terminal 54 . therefore , insertion of the memory card 11 can be detected . since the switch 14 for inhibiting writing is located in its forward position , the switch 14 is not pressed against the pressure contact portion 54 b of the first movable contact terminal 54 . consequently , the movable contact portion 54 a does not touch the fixed contact 53 . it is possible to detect that the card is in a write inhibit condition . if the write - inhibit switch 14 is located on the side of insertion as shown in fig1 , the switch 14 bears against the pressure contact portion 54 b of the first movable contact terminal 54 . therefore , the movable contact portion 54 a comes into contact with the fixed contact terminal 53 . it is possible to detect that the card is in a writable condition . when the memory card 11 is pushed in again , the other end 51 b of the lever 51 moves from the third support point 41 c to the fourth support point 41 d . concurrently , the locking pawl 56 is greatly pushed out into the locking recess 13 ( fig1 a ). however , when pushing of the memory card 11 is released , the other end 51 b of the lever 51 returns to the first support portion 41 a from the fourth support portion 41 d ( fig1 b ). the spring force of the coil spring 52 pushes back the slider 40 . the guide pin 57 is moved back along the guide groove 35 . as a result , the locking pawl 56 slides within the slide groove 42 and retracts . this unlocks the memory card 11 . it is possible to take out the card 11 by lightly pulling it out against the spring force of the resilient pawls 22 and 23 . since the resilient pawls 22 and 23 push against the memory card 11 , if it is pushed back by the spring force of the coil spring 52 , there is no danger that the memory card 11 will be ejected from the connector 20 . the case where the memory card 16 is not provided with a locking recess is next described by referring to fig1 and 15 . before the memory card 16 is inserted , the slider 40 is located near the opening in the connector 20 in the same way as the foregoing . the other end 51 b of the lever 51 is located at the first support point 41 a in the cam groove 41 . the guide pin 58 is located ahead of the guide groove 35 . when the memory card 16 not provided with a locking recess is inserted , the card 16 fits over the slider 40 . the resilient pawls 22 and 23 on the top shell 21 press the card 16 against the connector body 30 . if the card 16 is pushed in further , the slider 40 slides against the spring force of the coil spring 52 . concomitantly with this movement , the other end 51 b of the lever 51 moves from the first support point 41 a to the second support point 41 b . the guide pin 57 moves along the guide groove 35 . therefore , the locking pawl 56 biased inward rotates . however , the locking pawl 56 is merely pressed against the memory card 16 , because the card 16 has no locking recess . the input / output interconnects 16 of the memory card 16 are connected with their respective connector terminals 50 . when pushing of the memory card 16 is released , the spring force of the coil spring 58 pushes back the slider 40 . the other end 51 b of the lever 51 falls into the third support point 41 c from the second support point 41 b . this hinders return of the slider 40 . at this time , the locking pawl 56 does not engage a locking recess but the memory card 16 is pressed against the connector body 30 by the resilient pawls 22 and 23 . consequently , there is no fear of the card coming off . at this time , if the memory card 16 is forcibly pulled out , there is no danger of the locking pawl 56 being destroyed because it is merely pressed against the card 16 . if the memory card 11 having the locking recess 13 is inserted immediately thereafter , the locking pawl 56 can be pushed back and mounted to the slider 40 that has been locked , because the locking pawl 56 is merely biased inward . similarly , if the memory card 16 having no locking recess is inserted , the locking pawl 56 can be pushed back and mounted to the slider 40 that has been locked . when the memory card 16 is mounted within the connector 20 , one side surface of the card 16 bears against the pressure contact portion 54 b of the first movable contact terminal 54 , and the movable contact portion 54 a touches the fixed contact terminal 53 . furthermore , one side surface of the memory card 16 bears against the pressure contact portion 55 b of the second movable contact terminal 55 . therefore , the movable contact portion 55 a comes into contact with the first movable contact terminal 54 . if the memory card 16 is pushed in again , the other end 51 b of the lever 51 moves from the third support point 41 c to the fourth support point 41 d . if pushing of the memory card 16 is released , the other end 51 b of the lever 51 returns to the first support portion 41 a from the fourth support portion 41 d . therefore , the slider 40 is pushed back by the spring force of the coil spring 52 . the memory card 16 protrudes out of the connector 20 . it is possible to take out the memory card 16 by lightly pulling it out against the spring force of the resilient pawls 22 and 23 . since the memory card 16 is pressed against the connector body 30 by the resilient pawls 22 and 23 , if the card 16 is pushed back by the force of the coil spring 52 , there is no danger that the card 16 will be ejected out of the connector 20 . in the present embodiment described thus far , the resilient pawls 22 and 23 prevent the memory cards 11 and 16 from being ejected . it is to be understood that the resilient pawls 22 and 23 are not essential . they may be mounted if necessary . according to the present invention , the locking pawl engages the locking recess and becomes locked where a memory card provided with a locking recess is inserted . where a memory card provided with no locking recess is inserted , the locking pawl biased inward by a spring material is pressed against the side surface of the memory card . in this way , the memory card not formed with a locking recess is accepted . therefore , there is the advantage that a connector is obtained with which memory cards having different contours can be connected .