reflex is a wireless protocol developed by motorola, used for two-way paging, messaging, and low-bandwidth data. it is based on the flex one-way paging protocol, adding capabilities for multiple forward channels, multiple return channels, and roaming. it originally came in two variants, reflex25 and reflex50. "reflex50" was originally developed to support a messaging service launched by mtel in the mid 1990s, while "reflex25" was developed several years later to provide an upgrade path for traditional one-way paging carriers. the "50" and "25" signified "50 khz" and "25khz" channel spacing, although in reality both variants supported flexible channel configurations. the two variants were unified into a single protocol with version 2.7, which was released simply as reflex 2.7. devices compliant with "reflex 2.7" are backwards compatible with both "reflex25" and "reflex50" networks, with several new features to improve roaming, performance, and interoperability between different networks. "reflex" systems support forward channel speeds of 1600, 3200, and 6400 bits per second, and return channel speeds of 800, 1600, 6400, and 9600 bits per second. like flex, "reflex" is synchronous, based on 1.875 second frames and 4-level fsk modulation.