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  • Does Plivo support E.164 format calling?

    Yes, Plivo supports both inbound and outbound calls made using the E.164 format. If Plivo receives a request in a non-E.164 format, it will append a '+' sign, followed by the 'country ISO code' and the 'number' in the SIP invite and forward the call to the next leg.

    Any outbound calls made in a non-E.164 format will fail.

  • Does Zentrunk support SIP over TLS?

    Plivo Zentrunk supports SIP over TLS and media over SRTP.

  • What SIP request methods does Zentrunk SIP trunking support?

    Plivo Zentrunk supports INVITE, CANCEL, ACK and BYE methods, whereas SIP: Option, SIP: Subscribe and SIP: Register are NOT supported on Zentrunk.

  • What methods of authentication does Zentrunk SIP trunks support?

    Plivo supports the following methods for authentication:

    1. IP access control list-based authentication.
    2. Auth-based authentication with username and password.
    3. Both methods used together.
  • What is the Calls Per Second (CPS) limitation for Zentrunk SIP Trunking?

    By default, the CPS for Zentrunk is set to two calls per second per account and one call per second per Trunk. If you need higher CPS requirements, please contact our Sales Team.  For issues related to Zentrunk or any other queries, please submit a ticket with the Plivo Support Team.

  • Can I record a call on Zentrunk?

    Currently, Plivo's Zentrunk does not support call recording.

  • Will the Zentrunk SIP URI work with my softphone?

    Yes. Zentrunk SIP URI can be used to make calls from any softphone. Create an account on your softphone (e.g. X-Lite). Then, uncheck “register with domain and receive calls” under the account preferences.

    Here are two tutorials that walk you through how to configure your softphone and soft switch (e.g., FreeSWITCH or Asterisk) to work with your Zentrunk SIP endpoint.

    Zentrunk & FreeSWITCH configuration 

    Zentrunk & Asterisk configuration

  • Does my Zentrunk SIP trunk support SIP OPTIONS PING?

    Currently, you cannot send SIP OPTIONS PING to Zentrunk SIP trunks.

  • Is Plivo’s Zentrunk really secure?

    Your calls securely connect with IP authentication and credential-based validation. Zentrunk offers Transport Layer Security (TLS) for signaling encryption and Secure Real-time Transport Protocol (SRTP) for media encryption.

  • How do I increase the capacity of my Zentrunk SIP trunk?

    There is a default limit to your Calls Per Second (CPS) allowance. CPS indicates the number of calls that can be initiated every second. By default, each account can initiate one call per second. Please contact the Plivo Sales Team if you need a higher CPS for your account. The CPS limit applies to outbound calling.  

    There are no limitations to the number of concurrent calls you can make using Zentrunk. Zentrunk servers are elastic in nature. These servers can scale up or down depending on call traffic. No additional configurations are required to add more capacity. 

    Since Zentrunk SIP trunks are charged on a pay-as-you-go basis, you are only charged for the minutes you use.

  • How many connectivity endpoints or points of presence does Plivo Zentrunk SIP Trunking have?

    Currently, Plivo has six connectivity endpoints across five continents to ensure optimal voice quality and minimum latency. Please see below for a list of the regions where our PoP (points of presence) servers are located.

    • North California, USA
    • Virginia, USA
    • Frankfurt, Germany
    • Sao Paulo, Brazil
    • Sydney, Australia
    • Singapore

    How can I ensure that my call is going through the nearest region or PoP to avoid latency?

    When a call is initiated by the user, Plivo locates the closest PoP to handle the call based on the source IP. This reduces the delay and latency in establishing the call.

  • Is there a limit to how many Zentrunk trunks and IP access control lists can I create?

    There is no limit to the number of IP access control lists you can create with your Plivo account. The recommended number of trunks per account is 100.

  • Does Plivo Zentrunk SIP Trunking support T.38 Fax?

    Unfortunately, no. Currently, Plivo Zentrunk does not support T.38 Fax.

  • What codecs does Zentrunk SIP Trunks support?

    Currently, Plivo Zentrunk SIP Trunks support PCMA and PCMU codecs.

  • What DTMF types does Zentrunk SIP Trunking support?

    Plivo Zentrunk SIP Trunking supports RFC-2833.

  • What equipment do I need to be able to use Zentrunk SIP trunking?

    Plivo Zentrunk can work with any SIP-based device such as IP-PBX, Session Border Controller (SBC), or any softphone SIP client like Zoiper or X-lite. Please refer to the Zentrunk Getting Started Guide for more information.

  • Why am I being charged for abandoned and short calls?

    Voice calls while using Plivo’s services are subject to carrier regulations within both the region where the call is made and the region to which the call is received. When using the Plivo platform, the following conditions and surcharges will apply:

    • Abandoned calls during an applicable calendar month should be less than 20%. If more than 20% of total call attempts are abandoned calls during any applicable calendar month, Plivo reserves the right to charge for those calls. The customer will pay an abandoned call surcharge with respect to those abandoned calls in excess of the threshold. The percentage of abandoned calls is determined by dividing the total number of abandoned calls by the total number of calls. Abandoned calls are defined as calls initiated by Plivo that are zero (0) seconds in duration, where the end-user has not answered or has rejected/missed the call. The abandoned call surcharge is $0.01 per call.
    • Average Call Duration (ACD) during any applicable calendar month should be greater than ninety (90) seconds. If the ACD during any applicable calendar month is less than ninety (90) seconds, Plivo reserves the right to charge for those calls. The customer will pay an ACD surcharge equal to “the number of minutes a customer would have used if the average call duration would have equaled ninety (90) seconds with respect to the number of calls actually completed” minus “the number of minutes the customer actually used with respect to the calls actually completed” multiplied by “The ACD Surcharge”. The ACD surcharge is $0.012 per minute.
    • Short Duration Calls during any calendar month should be less than 5%. If, during any calendar month, 5% or more of the customer’s completed calls are short duration calls, Plivo reserves the right to charge an extra fee. The customer will pay a surcharge per short duration call. The short duration calls are defined as calls initiated by Plivo which are less than 15 seconds in duration where the end-user has answered the calls. The short call duration surcharge is $0.03 per call.
    • Incomplete calls to incoming toll-free numbers during any calendar month should be less than 5%. If more than 5% of total call attempts are incomplete toll-free calls during any calendar month, Plivo reserves the right to charge extra. The customer will pay the incoming toll-free call surcharge with respect to those incomplete calls in excess of the threshold. The percentage of incomplete calls to incoming toll-free calls is determined by dividing the total number of incomplete toll-free calls by the total number of calls. Incomplete calls to incoming toll-free numbers are defined as calls received by Plivo on a specific toll-free number that are zero (0) seconds in duration, where the Plivo customer who owns/rents the toll-free number has not answered or has rejected the calls. Incomplete calls may be subject to the incoming toll-free call surcharge of $0.10 per call.

    Here’s an example of how fees work in the instance of an ACD surcharge, for example. 

    If the call is a 10-second call, the surcharge for it will be (90 - 10) X ($0.012/60) = $0.016

    Any Plivo account usage that occurs due to a fraudulent attack(s) on your website or application will be your own responsibility. Plivo has no liability or responsibility towards any such attacks or traffic. Further, all costs related to the usage of services in such a scenario will need to be paid for in full by you. Plivo will provide reasonable assistance that you may require for any legal verification that is within our responsibility and ability to do so. 

    Note that in such a scenario, this can affect the credit rating of your company and any special privileges that Plivo may be offering to your company. Some Plivo services will require a verified address prior to service activation. In the event of any information request from a law enforcement authority or the end carrier, you will need to provide such information within a 24-hour period. You will be responsible to ensure that the end-user information is compliant with any applicable service restrictions. Plivo is not under contractual obligation to provide any subpoena or legal documentation while requesting for additional information.

    Fee Disputes. If you have any dispute regarding fees associated with your account, please contact us through our support portal at within 30 days of the date of the activity that generated such dispute. We will attempt to resolve the matter. Any and all refunds issued to resolve such a dispute will be issued as credits to your account. Iin no event shall there be any cash refunds. Disputes older than 90 days shall not be entitled to any refunds or credits.

    For more info: please read our Legal and Terms of Service.