SIP Commander - free portable softphone

SIP Commander is a free portable softphone that you can use to make and receive VoIP phone calls from your PC, iPhone or Android based smartphone.

SIP Commander like a telephone to let you make calls through your computer. Call anyone via the internet who also has a softphone installed and if you sign up with a VoIP gateway service company you call regular telephone numbers as well.

The advantage of using SIP Commander is that you can leverage low cost or free VoIP calls and you can connect to the company SIP PBX and work remotely.

Easy to use and powerful Windows program was designed for people who want to improve dynamic interactions with contacts and to manage contact information. It supports multiple SIP accounts and save calls history.

See all contact information for incoming calls. For example, you can see Firstname, Lastname, Birhdate, Company name and other information before call answering. Keep detailed records and notes in your call log about each call and contact.

You can use SIP Commander as a customer database, or personal contact address/phone book, working with groups for managing contact info of individuals and organizations with relationships. Phone numbers, emails, web pages, faxes, pagers, addresses, customer notes - you can save all this data in an organized format.

You can dial phone numbers in one click via Internet. Program has a simple intuitive interface and quick and easy contact lookup. Import and export features are also available.

Attractive and easy-to-use organizer & PIM will keep track of your contacts, addresses, distribution lists, manage your schedule, remind about appointments, and keep your daily notes in order, store your contacts and call by one click. The slick user interface makes it a snap to find addresses and phone numbers, enter reminders.

With its intuitive & familiar interface, users can seamlessly transition from a traditional hard phone environment into the world of Voice over IP. Also by making the navigation simple and user friendly, SIP Commander provides users with easy access to address book management.

The program detects DTMF user input, sends DTMF (Inbound, SIP INFO, RFC2833), supports G.721 A-law/Mu-law, GSM.610, Speex. You can select audio In/Out Devices.

What Is SIP? - Background
What Is SIP Background Introduction About SIP Overview Basics
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Background

The meteoric ascent of the Internet as a rival to the circuit-switched telephone network has given rise to strong economic and technological reasons for converged services and architectures. In order to assimilate telephony services with the ubiquitous technology of IP, a signalling protocol is required to set up and tear down connections.

A number of different communities put forward solutions, each coloured by their own priorities and interests. The Internet community wanted to introduce innovative services based on enhanced web-authoring tools like XML and more open, peer-to-peer protocols and call models. The IETF offered SIP.

SIP was originally intended to create a mechanism for inviting people to large-scale multipoint conferences on the Internet Multicast Backbone (Mbone). At this stage, IP telephony didn't really exist. It was soon realised that SIP could be used to set up point-to-point conferences - phone calls.

The SIP approach exemplifies classic Internet-style innovation: build only what you need, to address only what is lacking in existing mechanisms. Because the SIP approach is modular and free from underlying protocol or architectural constraints, and because the protocols themselves are simple, SIP has caught on as an alternative to H.323 and to vendor-proprietary mechanisms for transporting SS7 protocols over IP.