Bria is the defacto commercial softphone. It isnt free, but it is pretty much the standard from a commercial perspective.
There are lots of various SIP softphones (search for that term).
Skype ima opciju koja se zove Skype number i radi baš to, osim što onaj koji zove plaća cenu lokalnog poziva. Ali Srbija nije u podržanim zemljama... ne znam da li imaju toll free linije. Mislim ovo može da se reši ako firma ima centralu, i sve ide preko lokala.
Radio sam kao outsourcer za jednu firmu u Kanadi, i dobio sam svoj lokal a na računaru sam imao program koji prima pozive i preko koga mogu da zovem bio je Bria http://www.counterpath.com/bria/
Mada imaju i open source rešenja.
With us it's like this:
+=star (reddit uses stars for formating so I have to use +)
All our work phones work like any other, dial a number and it works. Dial asterisk/star room number (+10) and it will dial the room.
To transfer calls we just put in #1+room_number for assisted transfer and that we ask the guest if he wants to take the call or ##+room_number for direct transfer.
The guests in their rooms are marked with special restrictions. Basically if they ever want to dial a number it tells them:
You have $ which is X minutes. (We decided to have it setup like this. Like prepaid cards they put money on the phone in their room instead of charging later.)
To call the front desk they dial 0, to call a cab they can do that for free with +some_number_I_cant_remember. And they have a whole booklet of free numbers they can call.
Then we have some other rules, if lets say they dial the front desk (0) from midnight to 7AM all phones ring, otherwise just a special phone for night shift.
We even have it setup like this that if we're COMPLETELY FULL it tells them "No rooms, fuckoff" :D, or we sometimes just block/blacklist numbers with a special code we use.
AND THE BEST THING OF THEM ALL!
We have a little Arduino connected to the front desk bell. When they ring it it also makes the Arduino run a script that calls our wireless phones or even our mobile phones from a special number, letting us know there's someone at the front desk.
I just use my on mobile phone for everything. Everyone that has a smart phone got this app http://www.counterpath.com/bria/ works on android and iPhone. Has limitations so we can't use it offsite or when not working.
Basically if I'm taking a shit I can answer the phone on my iPhone :D
EDIT: These are just some of the awesome things you can do with VOIP :)
G-Doc's replacement, Well you know that there is not just one open source options. I do have a recommendation that might just work out better. Redmine -- BigBlue Button -- SVN/GIT "Revision control" -- and FreeSwitch. Redmine as a Project management solution. This allows you to create a Show Project and create custom work flow for task related to that project.. It also has a great Document and file management solution with Rev control natively.. What more the ability to integrate Revision control into redmine Dash board allow you to do more than just share documents. BigBlue Button is a calibration solution. with Recording and Conferencing capabilities. It is embedded into the redmine Dash-board Finally FreeSwith, -- Well BigBlue button uses Freeswitch to control the conference Rooms and WEB RTC for Video Conferences. What's more, you can link High def Video from a BREA "Counter Path" Client Direct into the FS sip reg. If you want a demo I can link it from my Production Environment.
http://www.counterpath.com/bria-for-linux/ http://bigbluebutton.org/ http://www.redmine.org/
I had the best luck with Bria for Android and iOS, but I still didn't like it that much. I haven't found a softclient that I've really liked.
http://www.counterpath.com/bria-android-edition.html
http://www.counterpath.com/bria-iphone-edition.html
I have about 1100 users working in 19 offices and at home on ShoretelSky. We've been customers since the early M5 days so all our handsets are Cisco and we still only deploy Cisco phones (we buy them referbished). While there have been a few rough patches over the years, most of them were actually before Shoretel bought them. Since Shoretel took over, the service and reliability has been excellent and even before I would give them a 8 out of 10. I just renewed our contract a few months ago actually.
We've been testing the IP48X phones and have not experienced the audio problem some are mentioning. We do prefer the Cisco phones feature-wise so we're sticking with them for now. Their mobile app does completely suck so we use Bria (http://www.counterpath.com/bria-iphone-edition/) for the mobile devices and xLite (http://www.counterpath.com/x-lite/) for PC softphones when we need it.
Their voicemail transcription service, Shoretel Scribe, is the best I've seen and is probably the #1 favorite feature of my users. All in all, and I hope I'm not jinxing things, My users and I are huge fans of ShoretelSky.
Buy some cheap Android handsets and install a sip soft phone on them. Bria by CounterPath is what we are using across all of our platforms (Windows/Mac/Android/iOS). You should look at their saas version as it gives you a means to manage the end points.
Counterpath Bria has a softphone for most platforms, definitely for Windows, Android, and iOS. I haven't used it in a touch interface on Windows, but have used it on Android.
If you are looking at multi-platform clients, Counterpath should be on the short list.