A surface wearable or implanted medical device suitable for delivering therapeutic agents to the body as well as monitoring and analyzing analytes in bodily fluids. Outbound traffic that is sufficiently similar to recently received inbound traffic is indicative of the presence of malicious code. The drive head consists of either a square drive head or a ratchet drive head. Further, the text entry is automatically sent to the second user if the preferences of the first user indicate that a text entry following the indicator is to be automatically sent to the second user.