Frequently asked questions regarding AltiGen Communications, Inc.'s SIP trunks.

This article aims to provide answers to frequently asked questions regarding the SIP trunking service sold by AltiGen Communications, not information about interoperability with other 3rd party SIP Trunks.

Contents

• General
  • Can I get AltiGen SIP Trunks outside of the 48 Continental United States?
• DIDs and Inbound Call Routing
  • What is the appropriate DID DNIS length for AltiGen SIP Trunks?
  • Should MaxCS servers be set to use the To: header or the Request URI (rURI) for the incoming DID number?
• Caller ID for outbound calls
  • How many digits should be used for transmitted caller ID?
  • Which value should I select as the SIP Calling Number's SIP Protocol Field?
  • Do I need to restrict the calling number to only send DIDs that I have purchased?
  • Is it sufficient to set the caller ID only in the system main number if users do not have individual DIDs?
  • I've ordered CNAME service for my DID, so why it is not displaying on the called party's phone?
• Trunk DID Forwarding
  • Is it possible to set a DID to forward to an external number if my phone system is down?
  • What is the difference between PSTN Forward and PSTN Backup?
  • When setting PSTN Backup forwarding, how should the target number be formatted?
  • How will we be billed for minutes on forwarded calls?
• Toll Free Numbers
  • How do I set the target destination for toll free numbers that I've purchased on AltiGen SIP Trunking?
• 911 Calling
  • What does it mean to have E911 service for a DID an AltiGen SIP Trunk?
  • What if I have not purchased E911 on any DIDs on the trunk, and someone dials 911?
  • Will the $75 fee for calls routing to the generic PSAP apply even if the caller hangs up before someone answers?
  • Can I opt out of 911 service?
  • How can I configure MaxCS to not route calls to a PSAP when a user dials "911"?
  • When does MaxCS know to send the E911 caller ID, rather than the regular caller ID?
  • What about if the user dials the route access code, followed by "1911"?
  • How do I test to make sure that my E911 configuration is set correctly?
  • Is there a way to tell if someone on the system has called the emergency number?

General

Q. Can I get AltiGen SIP Trunks outside of the 48 Continental United States?
A. Unfortunately we are not currently providing SIP trunking service outside of the 48 Continental United States at this point in time. If you require service outside of this area, please contact AltiGen's sales department to inquire about other possible trunking partners for your customer's location.

DIDs and Inbound Call Routing

Q. What is the appropriate DID / DNIS length for AltiGen SIP Trunks?
A. AltiGen SIP Trunks send 11 digits DNIS in the SIP Request URI (rURI)header, so all DID and DNIS entries in MaxCS should be configured using 11 digit lengths.

Q. Should MaxCS servers be set to use the To: header or the Request URI (rURI) for the incoming DID number?
A. In MaxAdmin's SIP Trunk Settings, the incoming DID number for AltiGen SIP Trunks should be set to "Request URI". Our underlying provider may use 10 or 11 digits in the To: header, depending on the origination of the call. The rURI for inbound calls is always normalized to the 11 digit target DID of the call.

Caller ID for outbound calls

Q. How many digits should be used for transmitted caller ID?
A. 10 digits should be used for all transmitted caller ID options.

Q. Which value should I select as the SIP Calling Number's SIP Protocol Field?
A. This should be set to the FROM Header with AltiGen SIP trunks.

Q. Do I need to restrict the calling number to only send DIDs that I have purchased?
A. While our underlying trunking provider should be able to handle any valid phone number as a transmitted caller ID, the display of caller ID information is highly dependant on the receiving end of the call. While it is not required to restrict the calling number to only DID numbers that are on the trunk, you may find it to be the best (and perhaps only) way to deliver numbers consistently.

Q. Is it sufficient to set the caller ID only in the system main number if users do not have individual DIDs?
A. This is not recommended because it will result in only 7 digits being sent as Caller ID to destinations such as 911. Best practice is to populate the E911 CID for every extension.

Q. I've ordered CNAME service for my DID, so why it is not displaying on the called party's phone?
A. Display of calling party name is a function of the receiving party's carrier. The CNAME system is similar in concept to DNS. When a carrier receives a call, they do a reverse look up of the phone number to get the calling party's name. Unlike DNS, which has defined Time To Live (TTL) values for records and have relatively rapid convergence of records, telco's update their database from remote sources much more sporadically. By purchasing CNAME service on a DID, you are registering the name to the number in the CNAME system, but we cannot provide any guarantee of time for the receiving party's carrier to update their data. If you are not seeing the CNAME data appear, please try calling a land line in a different locality (with a different carrier) to see if the result is reproducible with multiple providers.

Trunk DID Forwarding

Q. Is it possible to set a DID to forward to an external number if my phone system is down?
A. Yes. The "PSTN Backup" feature can be enabled in the AltiGen portal to allow for a forward target to be set for each DID when the trunks are un-registered. This fail over should start within two minutes of when the server goes down, and calls will begin to flow to the system as soon as the trunk gets registered after recovery.

Q. What is the difference between "PSTN Forward" and "PSTN Backup"?
A. PSTN Backup is the scenario described in the previous question: Calls will forward to the desired number, when the trunk is not registered. PSTN Forward is a hard, always on forward. In general, it is recommended that you configure this forwarding on the MaxCS server itself, so we do not expose the ability to set the hard PSTN forward on the trunks to our dealers. If you feel that you need to use a hard forward at the trunk / carrier level, please open a support ticket, and AltiGen's operations team will work with you to accommodate this if needed.

Q. When setting PSTN Backup forwarding, how should the target number be formatted?
A. It should be formatted as 11 digits (1+area code+NXX+XXXX).

Q. How will we be billed for minutes on forwarded calls?
A. Forwarded calls consume minutes at twice the rate of a normal call that is terminated on a MaxCS system. This is because there is one leg inbound to the trunk from the caller, and another leg outbound from the carrier to the target.

Toll Free Numbers

Q. How do I set the target destination for toll free numbers that I've purchased on AltiGen SIP Trunking?
A. Toll free numbers purchased from AltiGen are delivered on to the trunk in exactly the same manner as any other DID. This is different than many traditional telephony toll free number scenarios where calls to the toll free number get forwarded to a DID on the system. For AltiGen SIP Trunks, you would program inbound call routing for the actual toll free number itself.

911 Calling

Q. What does it mean to have E911 service for a DID an AltiGen SIP Trunk?
A. When purchasing E911 service for a DID, you are required to provide an address to which the DID becomes associated. Our service provider then uses that address to determine which public safety answering point (PSAP) to route calls if they are sent with that number as the DID. When the PSAP receives the call, they will be able to associate the caller ID with the address of record so that emergency service can be dispatched as needed.

Q. What if I have not purchased E911 on any DIDs on the trunk, and someone dials 911?
A. If an outbound call is placed to 911 with a caller ID that is not subscribed to E911 service, then the call is routed to a generic PSAP. This PSAP will have no record of the address associated with the DID, but they will be able to dispatch emergency services if the caller provides an address. Calls to the generic PSAP are charged $75 per call.

Q. Will the $75 fee for calls routing to the generic PSAP apply even if the caller hangs up before someone answers.
A. Yes, the fee is for any call ringing to the generic PSAP. As a side note, the best practice on any accidental call to 911 (local PSAP, generic PSAP, etc) is to let the operator answer the phone, and clarify that the call is a mis-dial. This will prevent unnecessary dispatch of emergency personnel.

Q. Can I opt out of 911 service?
A. No. For legal and liability reasons it is not possible to opt out of 911 service on AltiGen SIP Trunks.

Q. How can I configure MaxCS to not route calls to a PSAP when a user dials "911"?
A. AltiGen does not support this configuration. For liability reasons we will not assist with circumventing calls to 911. We are more than willing to assist with ensuring that your 911 configuration is correct however.

Q. When does MaxCS know to send the E911 caller ID, rather than the regular caller ID?
A. "Emergency Numbers" are defined in the MaxCS System Configuration dialog. Any call to an emergency number will use the E911 Caller ID. Note that if the "Country Relevant" tab has the country set as "US & Canada" that "911" is automatically, and irrevocably considered to be an emergency number.

Q. What about if the user dials the route access code, followed by "1911"?
A. Calls sent on AltiGen SIP Trunks with a destination of 1911 will be routed as an emergency call. To ensure that the E911 Caller ID is used, rather than the regular transmitted caller ID, please define 1911 as an emergency number in the "Country Relevant" tab of the MaxAdmin system configuration.

Q. How do I test to make sure that my E911 configuration is set correctly - particularly given that the test would be very expensive if the configuration is incorrect, and the call routes to the generic PSAP?
A. Test E911 configuration by calling 933 as described in this KB article.

Q. Is there a way to tell if someone on the system has called the emergency number?
A. Yes, there are several ways. Any extension can enable notification for when the emergency number is dialed. Additionally AltiServ.exe generates trap messages when the emergency number is dialed. For AltiGen hosted MaxCS Private Cloud systems, our monitoring station will automatically email dealers when we detect that an emergency number has been dialed, regardless of the carrier. Additionally, if the call is routed to the generic PSAP, notification of the fee will be sent out as well. This should occur within 15 minutes of the call taking place.