Does this modem have CTR21 certification?

Yes, the equipment has been approved to [Commission Decision CTR21] for pan-European single terminal connection to the Public Switched Telephone Network (PSTN). However, due to differences between the individual PSTN's provided in different countries, the approval does not, of itself, give an unconditional assurance of successful operation of every PSTN network termination point. In the event of problems, you should contact your equipment supplier in the first instance.
This equipment is designed to work with PSTN networks that accept analog signals. Multi-Tech Systems does not currently know of any operating difficulties.