The ADTRAN TSU ESP is a full-featured T1/FT1 Data Service/Channel Service Unit (DSU/CSU) with an integral SNMP agent and optional, modular dial backup (DBU) capabilities. It provides an interface between T1 or Fractional T1 service and the customer's data terminal equipment (DTE). The TSU ESP provides access to traditional dedicated point-to-point T1 circuits as well as Frame Relay services.The TSU ESP supports synchronous data rates from 56 kbps to 1.536 Mbps at Nx56 or Nx64 kbps. A single V.35 physical interface provides a connection to the end user's DTE. Embedded SNMP and Telnet are available through the integral SLIP or an optional 10BaseT Ethernet port when configured with the plug-in ESP Ethernet card. Through the Management Information Base (MIB)-II standard and an ADTRAN supplied enterprise MIB, the TSU ESP can be configured and monitored using standard SNMP network management programs such as HP OpenView, Netview and SunNet Manager. The Dial Backup capability of the TSU ESP allows for automatic switched backup in the event of a dedicated T1 line failure. The Dial Backup is accomplished through a family of plug-in ESP DBU cards. Several versions of ESP DBU cards are available including 4-wire Switched 56, 2B+D ISDN, and External DCE. When a failure condition occurs on the T1/FT1, the DBU card utilizes the switched network (ISDN, 4-wire Switched 56) or DTR dialing (External DCE) to initiate a call to the remote end. The user can choose whether the unit automatically or manually reverts to the dedicated circuit when it is restored. Optional Weekend and Time of Day Dial Backup lockout options are provided in the TSU ESP DBU option menu. The TSU ESP responds to standard loopback commands from the telephone company central office. In addition, the user has several built-in test capabilities. These include V.54 remote loopback and 511 BERT test patterns. Complete unit control and configuration are available through a 16-key pad and a two-line, 16 character LCD display. A VT 100 terminal configuration and control mode is also available through the control port. Optional Windows-based PC Management is available through the T-Watch PRO software package. Flash download capability is implemented for installation of new features and future enhancements.