A bit of a background. Thinking of moving away from a softphone, which I predominantly use for a long distance calls, a few months ago I got myself a Linksys SPA3000, got it configured (was not easy, but ...) only to find that I wasn't really using it (kept using internet softphone application to long distance calls as it was easier).

But when I got a mobile phone with a SIP client - I almost immediately stopped using softphone in favor for SIP calls on mobile.

Since running Linksys SPA3000 all the time is not going to get our Earth any greener, I am wondering thinking of getting rid of it. But at the same time (since I am not very knowledgeable in a phone technologies) - I would like to ask - what I am missing (features, etc) by not using VoIP on a landline?

Just to get things straight (because I know I could be misusing the terminology): when I say "VoIP" I mean - making cheap long distance calls using the landline phone connected to VoIP router (connected to the internet router with a cable), and when I say "SIP" I mean making cheap long distance calls using the SIP client on a mobile phone (connected to the internet wirelessly).


3 Answers 3


First, a clarification. "VoIP" is a buzzword that refers to any form of Voice-over-IP, including that carried by SIP (Session Initiation Protocol) and its associated protocols.

If your landline and mobile phone are configured to use different providers then you'll miss out on any emergency services (911, 119, 999, etc.) provided by the landline provider. If both devices are configured for the same service or if your landline provider doesn't have emergency services then the only thing you'll miss is being able to use your old landline handset.

  • in many countries it is required by law to have 3 digit emergency service dialing, whether it is a landline or voip line.
    – MaQleod
    Aug 23, 2011 at 6:30

As Abrams said both VoIP and SIP use IP protocol and you are essentially making phone calls using the Internet as the transport mechanism.

As fas as the difference goes between a 'VoIP land line' and a SIP client on a cell phone, there are not too much differences when you are just making a call.

But, in a properly set up VoIP, a digital or an IP phone can provide a host of features that may all not be available on a cell phone. Some of these are voice clarity, find-me, follow-me, unified messaging, unifies communications and so on. In addition, all this depends on the apps you are running on the cell phone. Some companies such as Toshiba Telecom (http://telecom.toshiba.com) have developed apps that provide nearly all the features in the cell phone.

Ultimately it depends on two things - (1) what is your predominant use of the VoIP circuit - personal or professional? and (2) how well you have set up your VoIP system back in your office. As we said before if you just using VoIp (or SIP on your cell) to make calls and save money, it really does not matter too much.


I tried to think of any particular feature that you might miss and.. here is my list:

  • Very long calls (mobile phones battery is drained out quickly with wifi on and compression w/o dedicated hw chips)
  • More codecs available on hw phone
  • More NAT traversal options on hw phone
  • Three-way Conference Calling with local mixing on the hw phone
  • SPA3000 has also a FXO line which can be used for backup in case SIP is down

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