Components inside the wireless module:

Toshiba TB31261AF cordless telephone RF chip

Ceramic resonators

Unidentified square ceramic components with 2 cylindrical holes in them horizontally (anyone who has an idea what they are, please comment.)

The back of the board says that it was manufactured on August 29, 2001, making the phone 14 years old at the time of writing.

Interestingly, the Toshiba TB31261AF is designed for a 900MHz cordless telephone, but this is a 2.4GHz model.