SIP VOIP

The Session Initiation Protocol (SIP) is a signaling protocol, widely used for multimedia communication, video conferencing, streaming multimedia distribution, instant messaging, presence information and online games. SIP management across firewalls integrates many forms of communications with data and processes safely across corporate and consumer boundaries. This opens a huge opportunity for integrated instant messaging and VoIP services to be brought to the mainstream and mission-critical environments.



#1 Call Centric

Pay Per Call Rate Plan   (Phone-To-Phone)

Are you the kind of person that is unpredictable, one day making hours of cal...
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Free N/A Pay per-call
2 Call Centric

North America Unlimited Rate Plan   (Phone-To-Phone)

If you call the United States and Canada a lot, this is the plan for you. Wit...
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Free N/A $ 19.95
3 VOIP.com

Unlimited Monthly   (PC-To-Phone)

price/month $19.95
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Free N/A $ 19.95
4 VOIP.com

Unlimited Yearly   (PC-To-Phone)

$199.00 for the entire year! Get unlimited calls to the US, Canada and PR wit...
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Free N/A $ 16.58
5 VOIP.com

Business 1800   (Phone-To-Phone)

1,800 minutes to anywhere in the US, Canada and Puerto Rico
Additional...
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$ 19.95 $ 9.95 $ 24.95
6 VOIP.com

Business Unlimited   (Phone-To-Phone)

calling minute unlimited
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$ 19.95 $ 9.95 $ 34.95
7 VoicePulse

SIP Trunking (Prepaid)   (Phone-To-Phone)

US48 Outbound Minutes $0.005 - $0.019/min depending on destination
Eq...
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Free N/A Pay per-call
8 Zingo Telecom

Basic   (Phone-To-Phone)

Basic is a low entry-point plan perfect for those who want an inexpensive, oc...
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Free $ 9.95 $ 9.95
9 Zingo Telecom

Plus   (Phone-To-Phone)

Plus is a highly-competitively priced package for customers who want a full-f...
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Free $ 9.95 $ 14.95
10 Zingo Telecom

Residentail Unlimited   (Phone-To-Phone)

Residential Unlimited comes with the works. Unlimited calling to the continen...
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Free $ 9.95 $ 19.95
11 Zingo Telecom

Business Unlimited   (Phone-To-Phone)

Combining the powerful included features within the Linksys SPA-9000 IP-PBX p...
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Free $ 9.95 $ 49.95
12 Zingo Telecom

Saver Basic   (Phone-To-Phone)

Saver Basic is a low entry-point plan perfect for international users who wan...
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Free $ 19.95 $ 9.95
13 Zingo Telecom

Saver Plus   (Phone-To-Phone)

Saver Plus is a competitively priced package for international customers who ...
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Free $ 19.95 $ 19.95
14 Zingo Telecom

Saver Residentail Unlimited   (Phone-To-Phone)

Saver Residential Unlimited gives you unlimited calling to the continental US...
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Free $ 19.95 $ 24.95
15 Zingo Telecom

Saver Business Unlimited   (Phone-To-Phone)

Saver Business Unlimited provides an all-in-one package for small businesses ...
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Free $ 19.95 $ 59.95
16 ATandT

Calling Plan A (US LD only)   (Phone-To-Phone)

ATandT IP Flexible Reach (Calling Plan A) is a long dist...

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Free N/A $ 20.00
17 ATandT

Calling Plan B (Local and US LD)   (Phone-To-Phone)

Calling Plan B includes, in addition to what is included i...

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Free N/A $ 30.00
18 ATandT

Calling Plan C (Local and LD Package)   (Phone-To-Phone)

Calling Plan C includes:
300 minutes of Outbound Interstate (Inter- an...
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Free N/A $ 70.00
19 ATandT

Calling Plan D (ATandT IPTF)

Calling Plan D includes:

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Free N/A Pay per-call
20 ATandT

Calling Plan E (ATandT Voice DNA for Small Business Service only)

Calling Plan E includes:

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Free N/A $ 45.00
21 Nuvio

nConnect   (Phone-To-Phone)

Nuvioandrsquo;s nConnectandtrade; is a cutting edge solution that will save y...
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Free N/A $ 24.99
22 Easy Office Phone

SIP Trunking   (Phone-To-Phone)

SIP Trunking is perfect for those organizations who already have an on-site I...
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Free N/A $ 39.99

Although several other VoIP signaling protocols exist, SIP is distinguished by its proponents for having roots in the IP community rather than the telecom industry. SIP has been standardized and governed primarily by the IETF while the H.323 VoIP protocol has been traditionally more associated with the ITU. However, the two organizations have approved both protocols in some fashion.
Many VoIP phone companies allow customers to bring their own SIP-capable telephone sets, or softphones. The new market for consumer SIP devices continues to expand.
The free software community started to provide more and more of the SIP technology required to build both end points as well as proxy and registrar servers leading to a modification of the technology, which accelerates global adoption. SIPfoundry has made available and actively develops a variety of SIP stacks, client applications and SDKs, in addition to entire IP PBX solutions that compete in the market against mostly proprietary IP PBX implementations from established vendors.