The SP505 is a monolithic device that supports eight (8) popular serial interface standards for DTE to DCE connectivity. The SP505 is fabricated using a low power BiCMOS process technology, and incorporates a Sipex patented (5,306,954) charge pump allowing +5V only operation. Seven (7) drivers and seven (7) receivers can be configured via software for any of the above interface modes at any time. The SP505 requires no additional external components for compliant operation for all of the eight (8) modes of operation. All necessary termination is integrated within the SP505 and is switchable when V.35 drivers, V.35 receivers, and V.11 receivers are used. The SP505 can operate as either a DTE or DCE. Additional features with the SP505 include internal loopback that can be initiated in either single-ended or differential modes. While in loopback mode, driver outputs are internally connected to receiver inputs creating an internal signal path convenient for diagnostic testing. This eliminates the need for an external loopback plug. The SP505 also includes a latch enable pin with the driver and receiver address decoder. Tri-state ability for the driver and receiver outputs is controlled by supplying a 4-bit word into the address decoder. Seven (7) drivers and one (1) receiver in the SP505 include separate enable pins for added convenience. The SP505 is ideal for WAN serial ports in networking equipment such as routers, switches, DSU/CSU's, and other access devices.