There could be a million things wrong here. If you're using UCM, make sure the 2xxx phones are configured exactly like the 1xxx phone (e.g. calling search space, partition, etc.) Next, ensure you have a device target for the 2xxx phone or an agent targetting rule (I recomment ATRs they are amazing and you don't have to create another device target again). If you're using SIP you might need to update your CUPS/CUSP configuration. What error messages do you get when you send a call to a 2xxx phone?
david