End Echo Cancelling
DLE1-Ecan utilizes a Digital Signal Processor that detects
and cancels echo at the far end so that the packet network delay
has no impact on echo. The echo canceller samples the voice signal,
estimates and removes the echo, leaving the original speech. The
linear digital signal processor (DSP) models the echo and performs
the main echo cancellation task. A non-linear DSP processor is
then optimally employed to subtract out any residual echo or reflected
noise components. Echo is one of the most important factors that
affects voice quality. The presence of echo depends on both echo
level and echo delay. The primary source of echo is the impedance
mismatch at the hybrid that links a 2-wire analog loop to a 4-wire
digital trunk. The hybrid is not completely efficient in carrying
the electrical energy and a certain amount of the electrical energy,
or voice signal, is reflected back and may be perceived as echo.
Occasionally, acoustic feedback of certain phones also causes
noticeable echoes. These sources of echo are able to be cancelled
by the human brain as long as the time between our speech and
the echoed speech is not greater than 32 milliseconds.
| Engage's T1 Over IP products have
a minimum delay configuration, 1 millisecond packetization and
4 packet buffering, which introduces a delay of 5 milliseconds.
The amount of delay introduced by the packet network depends upon
its switching times, packet processing, packet jitter, transmission,
loading and quality of service configuration.
For example a network connection that utilize Gigabit Ethernet
switches, which introduce delays in the microseconds, does not
require echo cancellation. Wide Area Networks that traverse an
intranet or internet backbone have varying degrees of delay which
can easily exceed 28 milliseconds. Total round trip delays in
excess of 32 millisecond makes echo perceptible.
The IPTube’s Echo Cancellation provides the elasticity to
support clear connections across networks with significant delay
and packet jitter.
Private Line Services over IP
|Multi-Site Enterprises, Education Districts, Universities, National, State and Local Government, and Municipalities, incur significant recurring monthly costs for rigid-bandwidth leased lines used only for the interconnection of Phone Systems.
The IP•Tube DLT1-Ecan provides organizations with the ability to interconnect their existing phone systems over flexible bandwidth lines that are used to carry data, voice, and video. The Voice Only Leased Line Toll charges assessed by long distance and local carriers are eliminated or dramatically reduced by transporting voice traffic across LANs and WANs.
The most compelling option for the interconnection of T1 based systems
is when it can be accomplished over a Local Area Network. The deployment
of Fiber based LANS such as FDDI and Gigabit Ethernet, provides
organizations with high performance and high quality bandwidth that
is especially well suited for the interconnection of PBXs and Telecom
Wide Area Networks that have sufficient bandwidth and Quality
of Service provisioning result very significant cost savings especially
for Multinational Corporations. The IP•Tube DLT1-Ecan-C
with loss less data compression, detects idle and redundant data
within each voice circuit resulting in a 56 to 1 bandwidth savings.
WAN bandwidth is not consumed by silence or redundant samples.
Companies, that are able to provide IP Ethernet access networks
generate new revenue by offering traditional T1 leased line and
private line services, such as:
Cable operators connect traditional T1 leased line and private
line services over their hybrid fiber coax (HFC) cable networks.
HFC Cable network latency typically requires echo cancellation.
Metropolitan Area Networks
Metropolitan carriers with IP or Ethernet access networks
deliver traditional leased line and private line services.
Utilities generate new revenue by offering traditional T1
leased line and private line services over their fiber or power
- Telcos reduce costs by delivering profitable leased and private
line services over their flexible Ethernet infrastructures.
PBX Back Haul
The IP•Tube DLT1-Ecan provides CLECs with a way to back
haul T1 DS0s from a customer’s phone systems over their
Internet connection. The back hauled DS0s are connected to the
CLECs phone switch for connection to the Public Switched Telephone
Networks. Local Exchange Carriers are able to offer an economical
alternative to the local Phone Company.
Connecting phone systems across a wireless Ethernet connection
has a return on investment that is measured in weeks. Eliminating
the wired connection for the T1 based communication equipment
is made possible with the IPTube’s T1 Over Ethernet capability.
Echo Cancellation enables Wireless connections to support T1 Over
IP real time connections in a point to multipoint configuration.