A downhole telemetry system usable with a subterranean well comprises at least one pressure pulse generator, at least one pressure transmitter located in an internal tube space in the well and at least one pressure transmitter located in a tubing annulus. The system comprises a packer providing hydraulic isolation of the tubing annulus and at least one transmitter located below the packer and responding to at least one physical quantity characterizing a bottom-hole zone. The system also includes a data encoder located below the packer to read out the transmitter located below the packer and to respond to at least one physical quantity characterizing the bottom-hole zone, a pressure pulse modulator to modulate pressure pulses generated by the pressure pulse generator, a surface-mounted data-collection unit to converts the output data of the transmitters and to provide a surface-mounted data decoder with data for analysis.