Saturday, November 2, 2013

070 prefix phone numbers for 3G+ phones

Starting November 1st, 2013, Japanese phone numbers beginning with "070" will be available for use with 3G, LTE, and 4G cellular phones.

070 is not a new prefix for Japanese cellular phones. It's actually an old prefix: it was (and still is) used for Japan's last remaining 2G cellular network, called "PHS" in Japanese.

However, with PHS usage in decline and 3G/LTE/4G phone numbers in the 080 and 090 space being rapidly depleted, they have opened up parts of the 070 prefix for non-2G/non-PHS use:

  • If the first digit after the 070 is a five or six (ex. 070-5XXX-XXXX or 070-6YYY-YYYY), it is still a Japanese PHS number
  • All other number combinations could be either a PHS number or a 3G (or more advanced protocol) number
One interesting interoperability issue: because PHS 2G is not compatible with worldwide 2G GSM, they cannot send or receive SMS text messages.

That's how Japan's mobile email system got started: it was invented as an alternative to SMS.

From a consumer's standpoint, Japan's mobile mail alternative to SMS was superior: it allowed very long messages, it could interoperate and send/receive from internet email addresses, and allowed for rich content much like HTML mail.

From a carrier's commercial viewpoint, mobile email was a blessing because carrier provided email addresses, unlike phone numbers, could not to transferred to rival's networks (via MNP procedures), locking in customer loyalty; subscribers are hesitant to defect to other carriers because they would have to change/lose their Japanese carrier mobile mail email address.

It is only a recent phenomenon were people in Japan have begun to use SMS, although usage lags compared to carrier email. This is because of a few factors:
  • It is only recently that the government MIC mandated that carrier's SMS interoperate (send/receive SMS text messages between Japanese and international carriers)
  • Japanese 3G phones often had the SMS/MMS functionality buried in a deep submenu and referred to by strange brand names ("C-Mail" for KDDI/au SMS and "S!Mail" for Softbank MMS). Foreign phone operating systems, such as Android and iPhone, tend to feature the SMS/MMS features more prominently in their user interfaces. As Android and iPhone became popular in Japan, awareness of this functionality increased.
  • When the restrictions were lifted for SMS/MMS interoperability, internet services (both in Japan and overseas) started increasing the use of SMS as a verification method for Japanese customers.
Thus, sending SMS/MMS messages used to never work if sent to a 070 number. Now, people will need to know if the the 070 phone is PHS or not if they want to send an SMS.

PHS' popularity amongst the general public in Japan has dropped precipitously now that 3G is ubiquitous and even faster phones (LTE/4G) are available everywhere. However, there is one area where PHS is still used: corporations still use them for internal "employee assigned" phones as they're very cheap to buy and use in bulk with a corporate contract. They tend to be used as pagers, either connected to humans or machines.

When 3G was introduced, they first exclusively assigned the 080 prefix to the devices. They then eventually added the 090 prefix. During this time when 3G was new, some people were surprised to hear people tell them that their mobile number was "080", thinking that only "070" numbers were mobile numbers. Now, with the younger generation, some people may express surprise that somebody has a "070" number, as younger people associate the 070 prefix with old technology.

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