Have a client with a 6-7 year old Pan KXTD-816. He bought a new portable phone (checking model #) a year ago for his wife yet wants us to add it to his system. The person he bought the phone from said the KSU needed a new ROM. If so, who sells these upgrade ROM's? Also, I am very familiar with the KXTA-624 and 824 from a programming perspective. Is the 816 similar as far as programming from ext #1 and having a similar set of system programming codes?