Business SIP Provider

Provider	Plan Details	Monthly Rate *
	PBX SIP Trunking Compatible with nearly all PBX systems US-based support No contracts at all	$14.95	Details 143 Reviews
	Unlimited Extension Unlimited calling and long distance Company Call Record, Voicemail to email transcription No contracts, not setup or installation fees	$24.99	Details 33 Reviews
	RingCentral Office Unlimited calling and faxing No Commitment, No Setup Fees, No Installation	$19.99	Details 54 Reviews
	8x8 IP Trunking No contract required. Unlimited Calls (9 free countries) Save 50% or more	$29.99	Details 84 Reviews
	Smart PBX Unlimited Use of All Features Free Long-Distance No Contracts or Hidden Fees	$21.95	Details 135 Reviews
	Unlimited Business SIP Solution Best overall quality & service Unlimited calling in/out Month to month agreement	$24.95	Details 14 Reviews

*Taxes and other fees may apply.

Business PBX Solution

Provider	Solution Details
	Become an ITSP Now! Become a serious competitor in VoIP Immediately FULL Consultancy, Installation, Training & Support Sell Hosted IP PBXs, Biz Lines, Call Centre Turnkey Provisioning at your data center	Details

SIP responses, class 4: Request failures

• 400 Bad Request
• 401 Unauthorized: Used only by registrars. Proxys should use proxy authorization 407
• 402 Payment Required (Reserved for future use)
• 403 Forbidden
• 404 Not Found: User not found
• 405 Method Not Allowed
• 406 Not Acceptable
• 407 Proxy Authentication Required
• 408 Request Timeout: Couldn't find the user in time
• 409 Conflict
• 410 Gone: The user existed once, but is not available here any more.
• 413 Request Entity Too Large
• 414 Request-URI Too Long
• 415 Unsupported Media Type
• 416 Unsupported URI Scheme
• 420 Bad Extension: Bad SIP Protocol Extension used, not understood by the server
• 421 Extension Required
• 422 Session Interval Too Small
• 423 Interval Too Brief
• 480 Temporarily Unavailable
• 481 Call/Transaction Does Not Exist
• 482 Loop Detected
• 483 Too Many Hops
• 484 Address Incomplete
• 485 Ambiguous
• 486 Busy Here
• 487 Request Terminated
• 488 Not Acceptable Here
• 491 Request Pending
• 493 Undecipherable: Could not decrypt S/MIME body part

• SIP | SIP Response Codes | 1xx | 2xx | 3xx | 4xx | 5xx | 6xx