Before starting the test, the IUT has to be connected to the CTT.
For this purpose, the IUT shall support either:
- the DLMS/COSEM 3-layer, connection-oriented HDLC based communication profile (Mode E or direct HDLC mode); or
- the TCP/IP based communication profile.
The IUT may be connected directly or via a suitable modem. The connection shall be established before starting the test.
Testing of IUTs implementing other communication profiles is possible by using a suitable modem or via a test interface of the IUT supporting one of the profiles listed above.