Patent ID: 8660259

Claim:
A method for automatically configuring an interface unit for connecting a headset and a telephone having electrical connections, comprising: the electrical connections between the interface unit and the telephone include two pairs of electrical paths having a number of distinct permutation settings, and wherein each of the number of distinct permutation settings have a complementary setting together forming a number of distinct complementary setting pairs, wherein the two connections of a transmit pair of electrical paths are denoted TX+ and TX−, and the two connections of a receive pair of electrical paths are denoted RX+ and RX−, wherein the permutation settings have seven distinct configurations, which settings are denoted: 1 2 3 4 A TX+ RX+ RX− TX− B RX+ TX+ TX− RX− C TX+ TX− RX+ RX− D RX+ RX− TX+ TX− E TX+ RX+ TX− RX− F RX+ TX+ RX− TX− G TX+ RX+ RX− TX− and wherein permutation settings A and B are complementary, C and D are complementary, and E and F are complementary, further comprising the steps of: a) receiving a test signal, b) for each distinct permutation setting generating an output signal in response to the test signal c) determining a least preferred distinct permutation setting based on the output signals, d) selecting the complementary setting to the least preferred distinct permutation setting as a preferred setting.