OPhone, or OMS (Open Mobile System), is a mobile operating system running on the Linux kernel. It is based on technologies initially developed by Android Inc., a firm later purchased by Google, and work done by the Open Handset Alliance. The OPhone OS has appeared only on China Mobile phones, and the software was developed for China Mobile by software firm Borqs. A modified version of OMS has appeared on other carriers as Android+, also developed and maintained by Borqs.