Blockchain for Free Calling

blockchain free calling

eZuce Partners with ENUMER to Make this  a Reality for UniteMe and sipXcom

Free Calling and ENUM

Making free and easy calls across the Internet is always one of the dreams organizations have as they implement their VoIP systems.

The ENUM standard seeks to map phone numbers as defined by the E.164 standard ( to DNS names. ENUM as a proposed standard has been around since 2000 (RFC 2916 - ). The evolution of the original RFC has ended up resulting in the Internet Engineering Task Force’s (IETF) RFC 6116.

This slick standard (ok, for us DNS lovers it’s slick) allows systems to look up telephone numbers with a DNS query to then locate a SIP URI that calls can be directly routed to. So, awesome, the holy grail! Free calls across the Internet! Sign me up!

Sounds great right? So, why isn’t everybody using this already defined method to bypass calling through the PSTN? Well, it’s complicated...

ENUM is definitely in use. It’s used by large carriers to route their traffic around their networks as well as with their peering partners. It’s not exposed publicly because they, of course, want you to pay for their services.

Then there’s the whole problem of exposing your phone system to the Internet. You want to make darned sure that there isn’t a means to SIP dial through your phone system if it’s exposed to the Internet. There are systems scanning the Internet continuously looking for open SIP systems to make calls through.

There have been some attempts at delivering public ENUM services. There was which is no more. This service allowed individuals to register their own phone number and corresponding SIP address. Turns out this wasn’t overly secure and it was possible to hijack phone numbers and route them to other SIP addresses.


Let’s assume that administrators can properly secure their SIP systems. If there were a way to securely create and reference ENUM records users might flock to use ENUM. This is what Emercoin ( is hoping to do with their new service called ENUMER.

Emercoin is a cryptocurrency and a decentralized blockchain platform that can be used by a wide range of distributed trusted services. Beyond ENUMER Emercoin offers options for SSH, TLS, DNS and other services secured in their blockchain.

UniteMe, sipXcom & ENUMER

Uniteme and sipXcom provide complete enterprise-grade telephony, unified messaging, Instant messaging, audio conferencing, and many other features. sipXcom can be run along side your existing Cisco, Avaya, Mitel, Shortel or other PBX while you migrate users to the sipXcom system.

In addition to running Uniteme or sipXcom on a single server or cluster of servers (this can be a virtual or cloud environment), standards-based SIP desktop phones, soft clients, gateways, SBCs are supported.

Both Uniteme and sipXcom have had ENUM support since their debut in 2004. Since the demise of though there has been little opportunity to utilize this feature until ENUMER came along.

Configuration in sipXcom is easy. In System -> SIP Registrar, scroll down to ENUM Dialing and enter ‘’ as the base domain.

ENUM dialing







Now for every non-internal number dialed, UniteMe/sipXcom will perform an ENUM lookup at If the number isn’t found in ENUMER, communications system will proceed to route the call through the system’s normal dial plan.

Getting Your Number Listed in ENUMER

Getting your number listed with ENUMER is still a fairly manual process. You can follow their procedure here:

Additional Resources

See Emercoin’s ENUMER announcement:

Read the 3 Major Advantages to Running sipXcom in AWS and Get the Step by Step Guide to Configuring sipXcom to run in AWS below.

Written by Mike Picher

Mike Picher

Michael is an accomplished technologist and writer, he authored the first comprehensive book about the open source project and software from SIPfoundry. With more than 20 years of communications and information technology engineering and consulting experience, Michael brings a very pragmatic perspective to the unified communications and collaboration market. He has architected hundreds of enterprise and managed service provider networks and communications solutions. Prior to joining eZuce, he co-developed what became one of Maine’s largest technology consulting and software development firms. After successfully selling the consulting business, Michael turned his attention to the growing IP telephony space. He has helped successfully deploy some of the region’s largest IP based communications systems. Michael received his B.S. degree in Computer Engineering from the University of Maine. He continues to support and advocate for open source projects on a global basis most recently sponsoring the siXcom project. In his free time, Mike enjoys time on his 150 acre farm in Maine and enjoys motocross and considers himself a craft brew afficionado.

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