The 440A4 ISDN Terminating Resistor Adapter is used to balance the cable plant between the receiver and transmitter on the ISDN T-interface. It can be located or placed in the communication closet or at the work area. The configuration generally determines the placement of the adapter. The 440A4 consist of a 1 foot (305mm) section of a 4-pair cable connected to one end of a flame-retardant plactic housing. The cord is attached to the housing with the release tab of the plug cut flush to the jack. Removal requires the use of a small tool such as a screwdriver. The opposite opening of te housing is equipped with an 8 position modular jack.