The modes are defined in the EMV specification and you terminal vendor should be able to guide

However they are below

Mode 1

CDA supported AND CDA supported at 1st Gen when requesting an ARQC and at 2nd Gen when requesting TC and the terminal has gone online

(noting the CDA at 1st Gen TC is a given)

Mode 2
CDA supported AND CDA supported at 1st Gen when requesting an ARQC but not at 2nd Gen when requesting TC and the terminal has gone online

(noting the CDA at 1st Gen TC is a given and if the terminal did not go online)

Mode 3

CDA supported but it is not sent at 1st Gen when requesting an ARQC and it is not sent at 2nd gen when requesting a TC if hte terminal has gone online