(Part Number – 301-1544-04) Echo Cancellation – Echo Cancellation – T1 Over IP – Engage

Description

Overview

T1 Voice Over IP

The IP•Tube GT1-Ecan encapsulates full and fractional T1 circuits into IP packets. T1 Over IP connections provide for the interconnection of Channel Banks, PBXs and Telecom Switches via LANs, WANs, MANs, Satellite and Wireless Ethernet.

The IP•Tube GT1-Ecan ships with four T1 interfaces with Echo Cancellation and two 10/100 BaseT Ethernet Interfaces. 

Echo Canceller

The IP•Tube GT1-Ecan has four independent integrated T1 Echo Cancellers that cancel up to 64 milliseconds of Far End echo.  The Echo Canceller DSP detects and cancels echo at the far end so that the interconnecting packet’s network delay and jitter has no impact on echo. The echo canceller meets ITU-T G.164, G.165 and ITU-T G.168 requirements for echo cancellation.

Echo is one of the most important factors that affects voice quality. 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. Echo Cancellation is essential for T1 circuit emulation that involves voice connections to the PSTN and delay in excess of 20 milliseconds. Packet networks that traverse an intranet or internet backbone can easily exceed 20 milliseconds. The IP•Tube‘s Echo Cancellation provides the elasticity to support high quality voice connections across networks with significant delay and packet jitter.

The primary purpose to employ T1 Circuit Over Packet technology is to reduce or ideally eliminate the T1 leased circuit charges.  For an enterprise utilizing their existing intranet is very compelling. Typically these intranets are already handling a very demanding load with significant packet jitter.  The IP•Tube Echo Cancellation has jitter buffering greater than 100 milliseconds which is more than enough for the majority intranets and beyond the signaling delay tolerance of Voice PBX or Switch.

Choosing Wireless Ethernet for the transport of T1 Circuit Emulation is very popular since the circuit lease charges are eliminated.  Commercial Off the Shelf Wireless Ethernet radios do not perform well with full duplex T1 circuit emulation packet traffic that is configured to keep the round trip less than 20 milliseconds.  The IP•Tube‘s Echo Cancellation has the elasticity (Jitter Buffering and reduced Packet Frequency) to support the use of Wireless Ethernet for T1 Circuit Emulation.

Transparent Interconnect

The IP•Tube GT1-Ecan’s transparent operation maintains the proprietary signaling required to support PBX features such as call conferences, call forwarding, caller ID and SS7.

Signaling Support

Robbed Bit, PRI ISDN, SS7, and Proprietary out of band are supported. Echo cancellation is automatically disabled during FAX and Modem communications. Transparent support for Modem or Fax. Voice quality is not compromised.

Legacy phone equipment investment is preserved.

IP•Tube GT1-Ecan Standard Features

Dual LAN Interfaces

The IP•Tube GT1-Ecan’s transparent operation maintains the proprietary signaling required to support PBX features such as call conferencing, call forwarding, caller ID and SS7. Legacy phone equipment investment is preserved. Transparent support for Modem, Fax, or Data circuits. Voice quality is not compromised. 

Assured Delivery Protocol

In order to assure high quality communications over links with intermittent or noisy performance, such as Wireless Ethernet. The IP•Tube GT1-Ecan employs Engage’s robust Assured Delivery Protocol with the following benefits:

• Packet out of sequence detection and re-sequencing
• Lost packet retransmission with configured delay

IP•Tube GT1-Ecan Optional Features

Protector OPTION -PRO

The Protector option provides for automatic protection of the T1 circuit over independent IP packet routes. After conversion of the T1 circuit into IP packets, two identical packet streams are created. These duplicate packet streams are used to provide redundant IP connectivity to the remote location in either “Always-On” or “On-Demand” switch over modes.

The need to Protect Critical Communications is in high demand for the following applications:

• Public Safety Network Redundancy for Police, Fire and Medical
• Auto Recovery for Military Communication
• Delivering on Service Level Agreements
• Resilient Cellular Backhaul

Always-On

In “Always-On” mode, the Protector sends two identical packet streams simultaneously on the LAN1 and LAN2 ports of the local IP•Tube GT1-Ecan-Pro. The remote unit monitors both LAN1 and LAN2 incoming traffic and on a packet by packet basis selects the best packet to use for conversion from IP back to T1. In most cases, switching of the receive packet source between LAN1 and LAN2 can be done without T1 circuit interruption.

On Demand Protection

In “On-Demand” mode, the Protector only sends the duplicate packet stream over the second IP connection (LAN2 of the IP•Tube) if a failure is detected on the first IP connection. “On-Demand” connections can be used for cost savings or bandwidth reasons. For example, the expense associated with a backup IP Satellite connection for a full T1 (non-optimized T1 over IP requires 2.5 megabits per second) would dictate transmitting duplicate packets only during a failure condition.

Alternator Load Balancing Option -ALT

The IP•Tube GT1-Ecan Alternator option alternatively sends the IP packetized T1 frames on LAN 1 and LAN 2. The Alternator option enables fractional and full T1 circuits to be split over two IP WAN connections such as xDSL. The Lossless Data Compression option can be combined with the Alternator option to minimize the bandwidth required from the alternative paths.

Lossless Data Compression Option -C

The IP•Tube GT1-Ecan continuously detects idle and redundant data within each T1 Voice circuit resulting in as much as a 56 to 1 bandwidth savings.TDM over IP WAN bandwidth is not consumed by silent or redundant circuits. (Note: Compression only supported with IP•Tube GT1-Ecan-C models)

Applications

Far End Echo Cancelling

IP•Tube GT1-Ecan utilizes Digital Signal Processors that detect and cancel 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 utilizes 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.

T1 Private Line Services over IP

Businesses, Education Districts, Universities, National, State and Local Government, incur significant recurring monthly costs for rigid-bandwidth leased lines used only for the interconnection of PBXs and Telecom switches.

The IP•Tube GT1-Ecan provides enterprises 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.

LANs

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 Switches.

WANs

Wide Area Networks that have sufficient bandwidth and Quality of Service provisioning result very significant cost savings especially for Multinational Corporations. The IP•Tube GT1-Ecan 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.

Broadband Service Providers

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

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

Utilities generate new revenue by offering traditional T1 leased line and private line services over their fiber or power line networks.

Incumbent Carriers

Telcos reduce costs by delivering profitable leased and private line services over their flexible Ethernet infrastructures.

CLEC PBX Back Haul

The IP•Tube GT1-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.

Wireless Ethernet

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 point or point to multipoint configuration with the elasticity required.