Is that possible add WS-C3750-48TS-E to ws-c3750e-48td stack?
Yes you can definitely stack a 3750 and a 3750E switch. The difference is , the 3750E has Stackwise Plus technology whereas 3750 is just stackwise technology.
However (assuming both switches having same ios versions) both switches will negotiate to Stackwise only(the lowest one). If both were E switches, then would negotiate to Stackwise Plus.
However, you can still add them to stack and surely you would not find much difference in latency or any kind of utilizations due to the stackwise and stackwise technology difference, however there is still a difference in both technologies.
As long as both switches are 3750s you can stack them. I would make sure u have updated IOS tho. Make sure they have the same version number. If the (major) version number is different, the there is a good chance the stack protocol versions are different.
Sent from Cisco Technical Support iPad App
View this link for stackwise interaction of mixed switch types.
This link was found via a google search with the words "cisco stackwise compatibility"