La Pasion

A passion for health and for life!

Net Telephony Has Come A Long Way

without comments

Voxware is the leader in the compression/decompression (codec) technology needed to prepare the digitized voice packets for transport over the Internet and to reconstruct the voice signals at the receiving end.

Routing the packets through the Internet can create significant delays, depending on the paths taken and the amount of congestion at the routing nodes. When packets are late or lost, the codec compensates by averaging over the gaps, impairing voice quality.

With its most recent offering, the VIPSuite software development kit, the Princeton, N.J., firm claims to have greatly improved the quality of two-way voice conversations over IP networks such as the Internet.

Voxware’s codec is frequency-based rather than time-domain-based, allowing it to extract more information from the speech stream and to reconstruct it more accurately for late or lost packets. Also, it sets up a feedback link so the receiver can tell the transmitter how best to packetize and ship the data based on measured packet delay and other network performance parameters.

VocalTec dominated early development with its InternetPhone, which was aimed primarily at computer hobbyists willing to accept poor voice quality and other inconveniences with the fledgling technology.

More recently, the Northvale, N.J., firm has targeted corporate users with a gateway server and teleconferencing software called Atrium. The servers bridge the Internet and the public telephone network, allowing point-to-point calling with the connection to the destination phone completed over a local loop.

Atrium works with the server, enabling phone users to participate as they would in a regular conference call. Participants with PCs can also view Windows-based documents as they talk into the microphone.

NetSpeak Corp., of Atlanta, Ga., has also introduced gateway servers to leverage its initial WebPhone client software. Its Network Component Architecture provides a blueprint for building interoperable multimedia networks using its IP telephone client and server products.

Among the new innovators is Aplio, Inc., of San Bruno, Calif., which recently introduced a stand-alone device for converting a regular phone into one able to make calls over the Internet.

With the Aplio/Phone, a caller dials a phone number in the normal manner and then pushes a button to converse over the Internet. The initial product limits calls to other Aplio/Phone users, but the next release will reportedly allow communications with any H.323-compatible device, including a PC with the appropriate Internet telephony software.

Larger vendors have typically focused on gateway servers for their foray into the Internet telephony or IP voice market.

Lucent Technologies’ Internet Telephony Server (ITS) family is based on a Compaq ProLiant 2500 Pentium platform running Windows NT. The ITS server is compatible with the H.323 IP telephony standard. It lets users send and receive real-time voice and fax messages over the Internet or corporate intranet, with fallback to the public telephone network in case of service degradation.

Cisco Systems also has announced a voice packet gateway solution which it says will be the first in a series of products to support voice and fax over IP networks.

Available initially for the Cisco 3600 router, the gateway allows a company to offload branch-office voice traffic from the public telephone network, for instance, and route it across the corporate intranet, eliminating toll charges. Likewise, interoffice fax could be routed across the intranet or through an extranet.

Since the gateway interfaces with existing phones, fax machines, key systems and PBXs, it makes the process of placing calls over the IP network transparent to users. Cisco says it has developed a framework with its IOS software that supports the H.323 specification and provides for seamless integration of voice, data, and call control.

Gateways change the economics of Internet telephony somewhat. A server is needed at each end of a call, which can be expensive if they are deployed widely.

Toronto-based Array Telecom addresses this issue with a bartering system for customers who use its Telegate server. When a user dials a call, the local gateway routes it to Array’s directory server in Ontario. The server locates the Telegate gateway closest to the destination being called and sends the compressed digitized voice packets to it over the Internet.

The receiving gateway reconstructs the voice signal and forwards it to the recipient over the public telephone network. Meanwhile, the initiating gateway automatically “pays” the receiving gateway with encrypted tokens. Software tracks the amount of minutes used and given by each server so that the using companies can reconcile their accounts.

Array is focusing on international calls initially since the savings are greater, and it already has a number of customers operating gateways in many cities throughout Europe, Asia, and North America.

The logical extension of this arrangement would be a public IP telephony service, and that’s where much of the action is taking place.

Qwest Communications International is about to become the first nationwide provider of IP telephony and fax services over its own network. At the same time, Bell Communications Research, the former technology unit of the regional Bell companies, says it will create an architecture for an IP telephony network through a new company, Soliant Internet Systems.

Qwest will charge 7.5 cents per minute for its service, which it says will reach 25 cities by mid-year. Because of the bandwidth available on its fiber-optic network, Qwest will not compress the digitized voice packets and anticipates minimal delays, so it expects voice quality to be comparable with the public phone network. Users will place a local call to a Qwest IP network node, enter a passcode, and then dial a phone number. The network will then complete the call.

Besides offering IP voice, fax, video and data services, Qwest says it wants to help customers develop applications that integrate the different media, serving as a systems integrator as well as service provider.

Bellcore’s Soliant Internet Systems says it will supply software that brings the intelligent routing of the public phone network to Internet telephony. Soliant will partner with a number of communications equipment manufacturers and, by year-end, expects to see the emergence of a public packet network for IP use separate from the phone network and independent of the public portions of the Internet.

Other new service providers include the Global Exchange Carrier Co. (GXC) of Abingdon, Va., Networks Telephony Corp. (NTC), and FNet Corp. of Westlake Village, Calif.

GXC’s service gives Internet-connected PCs the ability to connect with regular phones anywhere in the world for realtime voice conversations.

NTC, an Infonet Services Corp. spinoff, will use NetSpeak’s WebPhone for communications over Infonet’s data network. Users of the NTCVoice service will initiate a call by clicking on an icon on their PC.

FNet’s service uses voice gateways from parent Franklin Telecom, which have been deployed nationwide and interconnected via a corporate intranet and the Internet. Users access the FNet network with a calling card and private PIN number. During the call, the user can adjust delivery volume and network delay from the telephone keypad to counter network congestion and improve sound quality.

Written by Rod

October 4th, 2015 at 11:24 am

Posted in Uncategorized

Tagged with , ,

Leave a Reply