Techniques for measuring a one way delay between two handsets over an Internet protocol (IP) network utilize a delay measurement subsystem connected to both handsets and a procedure to couple a test signal to both handsets and measure the response to the test signal. The delay measurement subsystem is connected to a call originating handset to play an acoustic test signal to the transmitter of the originating handset. The delay measurement subsystem is connected to a call terminating handset to play the acoustic test signal to the transmitter of the call terminating handset and to record acoustic signals received on the call terminating handset. Signals recorded at the call terminating handset include a sidetone signal and a signal received from the call originating handset. The difference between the sidetone signal and the signal received from the call originating handset represents the delay through the handsets and the IP network.