An implantable, self-contained, user-attachable or detachable telemetry module plugs into an implantable medical device to provide or supplement one or more telemetry functions needed by a patient having certain health conditions. A user-attachable or detachable telemetry module allows a user, such as a physician or other care provider, to select a telemetry module and attach it to a medical device. Various types of telemetry are implemented as various user-attachable or detachable telemetry modules, each providing one or more telemetry functions suitable for a particular patient whose condition imposes a particular demand on telemetry. A care provider selects a user-attachable or detachable telemetry module most suited for the particular patient, which improves healthcare cost efficiency. One example of user-attachable or detachable telemetry module includes a radio-frequency (RF) transmitter-receiver circuit module and a lead carrying an antenna. In one example, the circuit module is away from the implantable medical device and coupled to the implantable medical device through the lead. In another example, the circuit module directly attaches to the implantable medical device.