VoIP phone test Software Interface

This interface software establishes an audio connection to a VoIP (voice over Internet protocol) phone. By simulating the phone’s VoIP network, it allows you to test the phone’s acoustical performance during a call using PULSE test software. The interface works by establishing a call between itself and the phone. Then it reassembles the packetized data in the network into a continuous signal stream. This is presented to the test system in a usable and calibrated analogue format, using a high-quality sound card.

USE SCENARIOS

• Verification of acoustic design of IP phone systems that use a LAN (local area network) or the Internet during R&D in the research lab
• Evaluation and refinement of speech processing for VoIP phones, such as echo cancellers, voice activity detection and multiband compression
• Objective and subjective evaluation of phone components such as noise suppressors, microphone input filters and receiver output filters
• Calibrating the audio interface used with the VoIP terminal
• Quality assurance and sample testing of VoIP terminals from the production line

IN USE

The interface – or network simulator – allows you to set up relevant VoIP terminal parameters, before a dedicated calibration procedure allows accurate compensation for the gain (or attenuation) presented by the sound card. Calibration uses a built-in generator to output a sinusoidal signal. During testing, the two level meters provide analogue displays of the input and output, with small digital readouts in dBm. 

We recommend using Brüel & Kjær’s USB Audio Interface ZE-0948 as the sound card.

CAPABILITIES

• Implements SIP (session initiation protocol) and RTP (real-time transport protocol) for transfer of audio 
• Stable delay that is known, and free from jitter or dropouts
• Codec encodes and decodes the audio
• Acts as a telephone exchange for VoIP terminals
• Monitors digital input and digital output level