SWITCH    VENDOR   TYPE     DESCRIPTION

                --------  -------  -------  -----------------------------

                1AES      AT&T     Analog   No. 1A ESS

                1ES       AT&T     Analog   No. 1  ESS

                2BES      AT&T     Analog   No. 2B ESS

                2ES       AT&T     Analog   No. 2  ESS

                3ES       AT&T     Analog   No. 3  ESS

                3XB       AT&T     E/M      No. 3  Cross-Bar

                4ES       AT&T     Digital  No. 4  ESS

                5AXB      AT&T     E/M      No. 5A Cross-Bar

                5ES       AT&T     Digital  No. 5  ESS

                5ORM      AT&T     Digital  Optical Remote Module

                5RSM      AT&T     Digital  Remote Switching Module

                5XB       AT&T     E/M      No. 5 Cross-Bar

                AXE10     Ericsson Digital  Stand Alone or Host

                AXRSS     Ericsson Digital  Remote

                DGTL               Digital  Generic Digital Switch

                DMS1/200  NTI      Digital  DMS 100/200

                DMS10     NTI      Digital  DMS 10

                DMS100    NTI      Digital  DMS 100

                DMS200    NTI      Digital  DMS 200

                DPN       NTI      Packet   Packet Switch

                EDX       Siemens  Packet   Packet Switch

                NC23      NEC      E/M      NEC Cross-Bar

                NEAX61E   NEC      Digital  NEC switch

                RLCM      NTI      Digital  Remote Line Conc Module

                RLCM-10   NTI      Digital  Remote Line Conc Module

                RLM       NTI      Digital  Remote Line Module

                RSC       NTI      Digital  Remote Switching Center

                RSCI      NTI      Digital  ISDN RSC

                RSLE      NTI      Digital  Remote Subscr Line Equip

                RSM                Digital  Remote Switching Module

                RSS       AT&T     Analog   Remote Switching System

                RSU                Digital  Generic Remote Switching Unit

                SXS       AT&T     E/M      Step by Step