Telephonic communications – Diagnostic testing – malfunction indication – or electrical... – Testing of subscriber loop or terminal
Reexamination Certificate
2000-12-28
2003-07-15
Tieu, Binh (Department: 2643)
Telephonic communications
Diagnostic testing, malfunction indication, or electrical...
Testing of subscriber loop or terminal
C379S027020, C379S027030, C379S027040, C379S010020, C379S022020
Reexamination Certificate
active
06594344
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention generally relates to voice communications. More specifically, aspects of the invention relate to voice communications over a network.
2. Description of Background Information
Voice communications systems enable at least two people who are not face-to-face to communicate as if they were. Latency, or delay, is an important consideration in the design and evaluation of such systems.
Because voice communications systems seek to emulate face-to-face communication, latency between a voice signal originating at the first person and the signal as it arrives at the second person must be kept to a minimum. When latency is below 100 milliseconds (ms), for instance, most people do not notice a delay when conversing with another person. Between approximately 100 ms and 300 ms, however, most people perceive a slight hesitation in the other person's response. Above 300 ms, most people are very aware of the delay, and effective communication is inhibited. When a voice communications system becomes loaded with multiple connections, latency values may increase.
Voice communications are increasingly being realized over networks. For instance, VoIP (Voice over Internet Protocol) involves sending voice information in digital form in “packets” using the Internet Protocol. A number of factors contribute to latency in VoIP networks, including delays inherent in the physical transmission media, compression and decompression delays, and routing and other such network delays.
An attempt to measure latency due to compression and decompression in a VoIP network has been made in the art. DTMF tones are played and time-stamped by software at an originating channel, and the tones are time-stamped by software at a receiving channel following compression and decompression phases. The difference between the time stamps is designated as the latency.
However, when designing and evaluating voice communications systems, engineers require more exacting latency measurements than those afforded by software methodologies.
Therefore, what is needed is a system and method that accurately measures latency in voice communications systems.
REFERENCES:
patent: 5375228 (1994-12-01), Leary et al.
patent: 5572570 (1996-11-01), Kuenzig
patent: 6091802 (2000-07-01), Smith et al.
patent: 6411679 (2002-06-01), Khasnabish
www.hammer.com/p_IPTel_Article.htm, “Internet Telephony,” 1998 Hammer Technologies, pp. 1-3.
Masri Ahmad
Nice Nir
Wilson Steven J.
Pillsbury & Winthrop LLP
Taylor Barry W
Tieu Binh
LandOfFree
Auto latency test tool does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Auto latency test tool, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Auto latency test tool will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3071946