A compact hotshoe-mounted radio transmitter giving TTL control of one or more external flashguns attached to a Flex TT5 receiver, or to trigger other guns using any other PocketWizard receiver. A flash can also be attached to its hotshoe. The Mini TT1 translates the digital data from the camera into an RF signal (433.42 - 434.42MHz channel) to give, unlike infra-red based systems, a reliable transmission, even in bright sunlight. HyperSync mode allows flash sync speeds of 1/500th sec or more to be achieved even if this is higher than the camera X-sync speed. A Utility Program enables all main parameters of the Mini TT1 to be set from a computer via USB connection, as well as managing any future firmware updates.