Over time, this issue was eliminated by switch billing instead of billing at the SMSC and by new features within SMSCs to allow blocking of foreign mobile users sending messages through it. By the end of 2000, the average number of messages reached 35 per user per month, and on Christmas Day 2006, over 205 million messages were sent in the UK alone. Text messaging outside GSM SMS was originally designed as part of GSM, but is now available on a wide range of networks, including 3G networks. However, not all text messaging systems use SMS, and some notable alternative implementations of the concept include J-Phone's SkyMail and NTT Docomo's Short Mail, both in Japan. Email messaging from phones, as popularized by NTT Docomo's i-mode and the RIM BlackBerry, also typically uses standard mail protocols such as SMTP over TCP/IP. SMS today , 6.1 trillion (6.1 × 1012) SMS text messages were sent, which is an average of 193,000 SMS per second. SMS has become a large commercial industry, earning $114.6 billion globally in 2010. The global average price for an SMS message is US$0.11, while mobile networks charge each other interconnect fees of at least US$0.04 when connecting between different phone networks. In 2015, the actual cost of sending an SMS in Australia was found to be $0.00016 per SMS. In 2014, Caktus Group developed the world's first SMS-based voter registration system in Libya. As of February 2015 more than 1.5 million people have registered using that system, providing Libyan voters with unprecedented access to the democratic process. SMS is being increasingly challenged by Internet Protocol-based messaging services such as RCS, Apple's iMessage, Signal, Facebook Messenger/WhatsApp, Telegram, Viber, WeChat (in China) and Line (in Japan), available on smart phones with internet connections. SMS Enablement SMS enablement allows individuals to send an SMS message to a business phone number (traditional landline) and receive a SMS in return. Providing customers with the ability to text to a phone number allows organizations to offer new services that deliver value. Examples include chat bots, and text enabled customer service and call centers. Technical details GSM The Short Message Service—Point to Point (SMS-PP)—was originally defined in GSM recommendation 03.40, which is now maintained in 3GPP as TS 23.040. GSM 03.41 (now 3GPP TS 23.041) defines the Short Message Service—Cell Broadcast (SMS-CB), which allows messages (advertising, public information, etc.) to be broadcast to all mobile