An automated conversion method and apparatus are provided to automatically detect the type of an incoming signal (e.g., SONET or Ethernet signal) at a site and to encapsulate outgoing data, or not, based on that detection to facilitate conversion to new infrastructure (e.g., TDM to Ethernet). The automatic detection can be achieved by alternating a search for a SONET signal or Ethernet signal received after a loss of signal or other similar event. Diagnostics of any prior valid transmission are retained in case the disruption was due to transmission quality problem rather than a change in the transmission protocol (i.e. SONET to Ethernet or Ethernet to SONET). The apparatus has an FPGA loaded by a microprocessor with the hardware configuration necessary to support either an IP or SONET configuration when change is detected in the format of the signal arriving at the optical port of the premises device.