Integrated downhole system with plural telemetry subsystems

A drilling method comprising:

• advancing a drill string while pumping a drilling fluid through a bore of the drill string during active drilling periods separated by flow-off periods during which a flow of the drilling fluid through the drill string is discontinued;
• and
• communicating telemetry data from a downhole system to a-surface equipment using one or both of EM telemetry and MP telemetry;
• wherein the drilling method comprises, at the downhole system:
• transmitting the telemetry data by the EM telemetry;
• monitoring an electrical output current of an EM telemetry transmitter;
• and
• if the electrical output current meets or exceeds a predetermined threshold, automatically switching to transmit the telemetry data by the MP telemetry;
• wherein:
• the telemetry data transmitted by the EM telemetry comprises a predetermined set of sensor readings;
• said automatically switching to transmit the telemetry data by the MP telemetry comprises transmitting a reduced set of the sensor readings by the MP telemetry;
• and
• the reduced set of the sensor readings comprises some or all of the sensor readings of the predetermined set of the sensor readings presented at a reduced data resolution, wherein the reduced data resolution uses fewer data bits to represent the some or all of the sensor readings of the predetermined set of sensor readings included in the reduced set of the sensor readings than a number of data bits used to represent corresponding ones of the sensor readings of the predetermined set of the sensor readings transmitted by the EM telemetry.