DND ON is absolutely correct... and the answer to your question is no, well, most likely not. There are other considerations like software version, license key, compact flash, etc.
Or are you referring to a MiVoice 5000, which is completely different than the MiVoice Office 250 (formerly the Mitel 5000 CP)... the MiVoice 5000 is a rebranded Aastra product.