What are the differneces?
No idea!
Out of all the one's we've shipped, telling people they are 100% inter-changeable, we've NEVER had to return/exchange one for the other!
I know that the 5000 requires the 53xx IP to interace Unified Communicator Express and Advanced...
Isn't the biggest difference that the 52xx series will take the transformer type power supply and the 53xx series requires the power brick and has no plug for the transformer type power supply?
5212 is half duplex speaker phone and 5312 is full duplex