SNLS579A April 2018 – November 2018 DP83TC811S-Q1
Time domain reflectometry helps determine the quality of the cable, connectors and terminations in addition to estimating OPEN and SHORT faults along a cable. The DP83TC811S-Q1 transmits a test pulse down the attached twisted-pair cable. Transmitted pulses continue down the cable and reflect from each imperfection and fault, allowing the device to measure the time to return and strength (amplitude) of all reflections. This technique enables the DP83TC811S-Q1 to identify cable OPENs and SHORTs.
TDR is activated by setting bit in the TDR Register 0x001E – Time Domain Reflectometry Register. Cable diagnostic status is obtained by reading bits[1:0] in the TDR register. TDR runs are stored in the TDRR Register 0x016B – TDR Results Register. When more than one fault is present, additional locations are identified by the TDRLR1 Register 0x0180 – TDR Location Result Register #1 and the TDRPT Register 0x018A – TDR Peak Type Register.