The 606 NOT ACCEPTABLE is one example of a SIP error code that you may receive back from SIP.US when placing outbound calls. The 606 is typically related to an invalid Caller ID, and you can receive this error back if your outbound routes have not been configured correctly to send a legitimate FROM header. Please ONLY send VALID numeric values in a preferably 10-digit format (for our North American clients).
Example: NXXXXXXXXX (1112223333)
Your TO and FROM headers should also be addressed to our SIP gateway you are registered with, so the full headers should read something comparable to the following example:
Example: NXXXXXXXXX@gw4.sip.us (1112223333@gw4.sip.us)
Nearly all PBX systems support setting custom Caller IDs in the FROM header of a SIP INVITE, but the methodology for applying it depends on the device manufacturer. SIP.US is not familiar with every PBX on the market and Support cannot advise you on how to configure the FROM header for your SIP device.
If you suspect your Caller ID is the issue, we recommend reviewing the "Call Detail Records" (CDRs) in our Customer Portal under the "SIP Trunking" tab to see if what we receive matches what you intend to send. If the Caller ID is invalid, you will need to recheck your configuration.
If you do not see your call examples, you may open a ticket with Support and we will inspect the SIP Invite headers for possible formatting errors. In order for us to locate the call, you will need to provide us with the Trunk number, the date and time (from the past 24 hours), the number you are calling to, and the number you are calling from.
SIP.US additionally offers a way to implement a Caller ID Override via our Customer Portal. This feature will rewrite whatever you send us in your FROM header with the input in the Customer Portal. To implement a Caller ID Override, navigate to the "SIP Trunking" tab and then "SIP Trunks". Choose "Modify Trunk" and then enter the number you are calling From in the "CallerID Override" field and submit the changes.
If you have any questions regarding outbound Caller ID and the ever important FROM header, please feel free to email us at support@sip.us.