Answer:

SENDER

Answer	Crossword Clue
SENDER	Dispatcher
SENDER	"Return to ...." (Presley tune)
SENDER	"Return to .."

SENDER	Email origin
SENDER	One in line at the post office
SENDER	Person who e-mails
SENDER	E-mailer
SENDER	Transmitter
SENDER	Return recipient
SENDER	Word in an Elvis title
SENDER	Elvis Presley's "Return to ..."

SENDER	"Return to ..."
SENDER	E-mail user
SENDER	Shipping worker
SENDER	One might get a return
SENDER	"Return to .." (Elvis tune)
SENDER	Poster
SENDER	E-mailer, for one
SENDER	Messenger-service client

SENDER	E-mail mailer
SENDER	E-mail initiator
SENDER	One mailing a letter
SENDER	Wireless operator.
SENDER	Transmitter.
SENDER	Broadcaster.
SENDER	Radio transmitter.
SENDER	Telegraph man.

SENDER	Telegraph office employe.
SENDER	Man at the telegraph key.
SENDER	Radioman.
SENDER	Telegrapher.
SENDER	Return addressee.
SENDER	Telegraph device
SENDER	Postal term
SENDER	Letter-writer

SENDER	Mailer
SENDER	A ham, sometimes
SENDER	One making dispatches
SENDER	Spaniard who wrote "Dark Wedding": 1943
SENDER	U.P.S. customer