A.standby mode

B.incoming call

C.no network connection

D.normal operation

A.as a public switched telephone network device

B.as a media switched telephone network device

C.as a packet telephony network device

D.as a circuit-switched telephone network device

A.They operated at a high expense.

B.They produced high-resolution image quality

C.They had not been invented yet.

D.They produced an unreliable image quality

E.They operated at a high frame rate