Panasonic KX-TES - Manual (Page 59)

5. Communicating Within Your Office
DBS-32-755 Issued April 2000 57
Note 2: On the large-display phone, you can also use the MSG key to
respond to callback messages (requires DBS software version CPC-AII/B v.
8.0 or higher, CPC-S/M, v. 2.0 or higher, or CPC-EX v. 1.0 or higher).