User's Guide

Nortel Networks Confidential
37
About the iBTS
Internal interfaces
The internal interfaces are the signals exchanged between the rTRM and the dTRM boards.
The samples are sent to the rTRM board and are converted into an analog signal. In the opposite
direction, the rTRM board digitallyconverts thesix receivedsignals and sends theresulting sample flows
to the dTRM board.
External interfaces
The external interfaces are the following:
digital shelf backplane interface: based on the dTRM board
CCM interface: based on the common HSSL interface