Digital Phone Service

Two main types of digital home services are available, namely, the Internet Telephony and Voice over Cable. The Internet Telephony is constituted of minor individual suppliers, whereas VOC is the provided by your local cable company. In spite of having several features matched with each other, they come with big differences. For instance, Internet telephony gets your calls connected through the public internet while the Voice over Cable applies the private networks. Internet telephony is solely based on the public internet and is therefore responsible for delays that can always occur due to this public network. In case of Voice over Cable, the cable provider’s private network is operated. In fact, you can even retain your old phone number when switching on to digital telephone service.

Internet Telephony

An Internet data service is offered by the ITSP, Internet Telephony Service Provider. This is done for using the telephone calls through VOIP technology. In order to transmit telephone calls as IP data packets most of the ITSPs use SIP H.323, or IAX. Well, you may use traditional telephones along with an analog telephony adapter that will provide RJ11 to Ethernet connection. Since 1995, net2Phone has been offering customers VOIP service.

Voice over Cable

Nowadays, the cable operators are making use of the existing bandwidth in their private networks for delivering high-speed Internet access. Gradually they are shifting towards providing integrated Internet and voice service over the cable spectrum. The voice service over these networks is called cable-based Internet protocol (IP) telephony. This particular technology is mainly targeted for home and overcome most of the challenges usually faced by the telecom carriers.

Cable as a Viable Telephony Medium

The reliable public telephone network service has been quite useful for the Americans and that too since almost a century. When cable comes to consideration as a proper alternative, there arises a good number of technical issues. One of the major one is the development of the cable infrastructure from a one-way, broadcast medium to a two-way, personal-communications medium.

Comparison between Half-Duplex and Full-Duplex Cable Infrastructure

During the later period of the 1950s, cable was first introduced in the United States. It was found that nearly every mile of buried cable contained half duplex that provided the broadband transmission from the downstream direction. The communication from the subscriber and then again to the head end was only possible through a telephone line. Due to this, the half-duplex lines prove quite burdensome for the premium TV services. It is also quite inconvenient for the Internet service as the outbound e-mail messages and HTTP requests have to be sent through the phone.

Well, in the recent years cable operators have been investing hugely for getting rid of the half duplex and upgrading full duplex. This step has been undertaken by them to get the most out of the demand for integrated data and voice services. Since the upstream transmissions are not as progressive as the downstream ones, the full-duplex lines will come up with sufficient transmissions for supporting the cable based IP telephony.

Direct Connection

Callers will be provided the benefit to receive and send their own voice packets that must be far better in comparison to the data packets. This is to ensure that the callers experience smooth and uninterrupted conversations. For the first time, the Data over Cable Service Interface Specification (DOCSIS) came out with ground rules all over the world for the transmission of the packets across cable networks. Later DOCSIS emerged out with a new version 1.1 with fine quality service and excellent security features. Moreover, this version also enables the facility of packet traffic where the cable operators will allow other traffic along with bandwidth availability.

Power Consumption

It is known to all that the traditional telephones consume all the power they need from the POTS lines. The public phone system has undoubtedly proved to be reliable and free from the effects of power outages. It is for this reason that the customer premises cable equipment solely relies on the local electric company for power puts users.

The IP-telephony system is built with a reduced instruction set computing (RISC) microprocessor to control the signaling functions and digit collection. Local Area Network (LAN) and universal serial bus (USB) are the major telephony peripherals that are affixed on a single chip in order to conserve power. For signaling processing several megabytes of high-speed Random Access Memory (RAM) is required. Similar amount of nonvolatile is required for the storage of telephony application, and that nonvolatile must be electrically reprogrammable for enabling online software updates.

DSP is a high-performance and low-power digital signal processor that will support the functions of the analog like the codecs, noise reduction, and echo cancellation.

Telephony Billing

Telephony billing is one of the most complex processes. In fact, most of the cable TV customers have to pay the same bill each month. A normal telephone bill includes monthly service fees on a recurring basis, international and long-distance charges and premium services.

The Voice-over-IP systems take telephony signals as digital audio by using speech data compression techniques. Two types of PSTN-to-VoIP services are available, namely the Direct inward dialing (DID) and access numbers. A caller will be connected directly to the VOIP user whereas through the access numbers the caller will be required to get an extension number for the called VOIP user.