OCN (オーシーエヌ), or Open Computer Network(オープン・コンピュータ・ネットワーク:Ōpun Konpyūta nettowāku), is the largest Japanese Internet service provider, with over 7 million subscribers.
[1] It is owned by NTT Communications Corp, one of the largest telecommunication companies in the world.
It offers dial-up and ISDN, DSL up to 50 Mbit/s and fiber up to 200 Mbit/s download and 100 Mbit/s upload.
Initially it started out as a data-only service, but more recently OCN Mobile One also offers an onseikake SIM card (音声対応SIMカード) that provides full service (data, SMS and voice) without requiring any calling app.
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