RMIT IT Test Lab's Matt Tett calls up your best options for smart, snazzy, and effective VoIP handsets.
This particular review follows on from our general overview of various vendors' VoIP technologies which was published in the August 2004 edition of T&B, "Voice over IP: security, stability, success". On this occasion we take a look at several handsets from each vendor.
There are, however, a few things that we need to cover before we get into the nitty gritty of the products sent to us for review.
Firstly, there is the difference between existing telephony systems (PSTN or POTS) and IP-based telephony systems. Traditional telephone calls have been made on what is known as a circuit-switched network.
This means that for the duration of a call the wires carrying that traffic are dedicated and occupied with that call only (proving to be quite inefficient). Internet Protocol (IP), with its packet-switched networking concept, takes data which has been converted from analogue (speech/voice) to digital (beeps/burps), and each connection can carry many different packets to and from many different senders and receivers.
Instead of having one single circuit that needs to be created and dedicated for the duration of the call and then broken down at the end of the call, the packet-switched device is connected to an "always on" connection. When required data is injected into that stream (and through the use of headers and routing) it is sent to its destination address.
The Internet is mostly an IP-based packet-switched network, therefore with the right configuration telephone calls can be placed from one node on the Internet to another.
There are many more technical factors that need to be considered such as packet relay times, jitter, Quality of Service (QoS), and network traffic prioritisation, as well as basic routing and firewall rules and dialling and numbering conventions.
Unfortunately not everyone in the world has an IP telephone and therefore at some point the traffic may need to go through a gateway to be converted from a IP-packet based call to a circuit-switched call on the PSTN (Public Switched Telephone Network) or POTS (Plain Old Telephone System).
Therefore, in practice, if you have offices in Sydney, Melbourne, and New York, you could implement a VoIP telephony system with PSTN gateways at each site.
This system would allow all internal company calls to be made for the price of the data packets transferred on the Internet instead of separate circuit switched calls usually required between each office.
It would also enable staff to make local toll charged PSTN calls from each of the branch offices. So a staff member in Melbourne can place a call to a client somewhere in New York and the first component of the call goes over IP from the Melbourne office to the New York gateway then from the New York gateway out over the PSTN to the client, thereby only incurring the cost of the Internet bandwidth used and the local call cost from the New York office to the New York client -- certainly cheaper than a direct PSTN call from Melbourne to New York.
This article was first published in Technology & Business Magazine in June 2005.
ISP's are currently battling the broadband war. The race for customer aquisition is aggressive. What is the holy grail... VoIP or basic broadband revenue? The answer lies in the current broadband price offerings of ISP's.
The cost savings of VoIP to corporations is unquestionable and the future economic benefits of widespread adoption is inevitable. One just needs to review the developments of such products as 'Skype' over the last 12 months to arrive at the realisation of just where VoIP is heading. Companies in Asia have even commenced manufacturing 'Cisco ATA type' devices which interface with skype enabling VoIP calls from your normal PSTN phone. The future of VoIP is cemented and the war for market share is definitely on.