noun
receiver; handset; telephone receiver
Refers to the part of a telephone or similar communication device that combines the speaker and microphone, i.e., the handset. Can also refer to a transceiver unit.
受付の電話の送受話器が壊れている。
The handset of the reception desk phone is broken.
無線機の送受話器を取って応答した。
I picked up the transceiver handset and responded.
Compound of 送 (そう, 'send'), 受 (じゅ, 'receive'), and 話器 (わき, 'speaking device'), literally a 'send-receive speaking device'.