Voice over IP

IP Phones – Advantages & Disadvantages (In comparison with Analog/Digital Phones)

This article throws some light on IP Phones (vs) Analog/ Digital phones. We will look at the differences between both by analyzing the advantages and disadvantages of either in each point that follows, without getting much in to the functionalities offered by the IP PBX (vs) Analog-Digital Mixed PBX.

  • Cost: The higher cost of IP Phones have been the most important factor prohibiting their mass adoption. Analog/ Digital phones, in comparison are available in all ranges (including highly cost effective models). But there are reasons (supported functionalities) for that added cost.
  • Diversity: There are different types of IP Phones. There are Soft-phones that can run on your computer, there are Voice over Wi-Fi phones that can operate using the wireless network, Soft-clients on mobile phones, and of course there are hard IP Phones on the desk. But analog phones aren’t available in so many forms.
  • Single Network/ Cable: With IP Phones there is a single network to build and maintain – The IP network. But with analog-digital phones, you need a separate network with telephone cables in addition to the IP network for data. A single cable from the network switch could connect to the IP phone’s two port switch and the computer could be connected using another network cable from there, but many companies have two cables coming from the network switch for redundancy.
  • Power: The good old analog phones do not require much power – what ever they need they can take it from the line itself! But the IP Phones need to be provided with a separate AC Power (or) Expensive Power Over Ethernet injectors/ switches that can send power along with data using the network cable.
  • Mobility: IP Phones can just be moved from one desk to another, and they will still pick up the config. information and retain your extension there. The Voice Over Wi-Fi Phones can work using the wi-fi network and hence can be carried around the building – making it a mobile land-line! Even the Digital Phones could do this using DECT technology, but it is proprietary, and one cannot access the data network using DECT base stations.
  • Usage over the WAN Network: You can use an IP Phones to register with an ITSP service provider to make long distance calls over the Internet economically. There is also no additional call charges when you use the IP Network (Connected with Leased Lines/ Internet) for calling between the branches, provided your data plan has unlimited bandwidth.
  • Shared Bandwidth: Since IP Phones share the network with computer data networks, the bandwidth is shared between computers and IP Phones. Its possible that over usage of either can affect the performance of the other, especially if end-to-end QoS policies are not enforced on the network. But analog/digital phones are on a separate network and even if the computer network goes down, the telephone network is  still On. In large scale deployments, it may be prudent to deploy some voice compression protocols.
  • Open Standards/ Multi-vendor connectivity: You could buy the analog phones from any vendor (not digital phones though) and the EPABX from any vendor and be assured that all the features/functionalities of the PBX would work on the phones. But with IP Phones, SIP is the open standard protocol, and only the PBX and IP Phones that support SIP would work together, and that too with slightly limited functionality. Some vendor’s IP Phones are proprietary and work only with their version of the IP PBX.
  • Security: While the only issue with analog phones is the possibility of ‘phone-tapping’ of external calls, IP Phones are vulnerable to some network attacks that can be directed on the VOIP system.
  • Remote Maintenance: IP Phones can be accessed and its configuration could be checked/changed from a remote network (or over the Internet), if appropriate permissions are given by the network administrator. This makes making configuration changes / maintenance easier.
  • Multiple Lines: While analog/digital phones could have one extension number (max), IP Phones could have multiple extensions (one for desktop & one for ITSP account over the Internet, for example).
  • Video Calling: IP Phones are moving in a big way to integrate video along with telephony. Users could use their web-cam to see the other person over the computer monitor and talk to them over the IP Phone, simultaneously; Or use special purpose video phones to see and talk over the large screen available over the IP Video Phones itself. This is available (in a limited way) with ISDN phones as well, but they are not very popular and need the digital ISDN network on both calling/receiving end.
  • Connecting to the Internet: With certain higher end IP phones, you could directly connect to the Internet right from your IP Phone with the built in browser. It may be possible to download and view pictures / download and listen to songs and ring-tones right from your IP Phone!
  • Computer Telephony Integration: This feature is available with Digital Phones (Making a call by clicking the contacts in your email client, etc), but IP Phones take the integration many steps forward – You can have a softphone right on your computer, you can click on a phone number embedded on a webpage to make an outgoing call through your corporate PBX, you can receive email notifications of your voice mails, you can even know who is calling/ what was their latest transaction details before picking up the call by integrating your IP PBX with business processes like the CRM systems, you can use API’s to integrate Google Maps to pop up the location of a caller – for example, and much more!


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Related Article: Voice over IP & IP telephony – An Introduction