In the old days, we Deaf people used to call our Deaf friends using a
"teletypewriter" (TTY) or later via a "Telecommunication Device for
the Deaf" (TDD) (Which most of us still refer to as a TTY.) Not
many people use TTYs any more since text messaging and videophones (VP) are
prevalent now. But you might still see this classic sign for "CALL"
that specifically refers to how Deaf people "call" each other.
CALL-(using a TTY)
If you mean "call" as in "give a name to" then you should use the verb form
of the sign for "NAME." This is the equivalent of name as in, "You should
name your dog 'Spot.'" Or "He christened his boat 'Sally' in
memory of his mother." To do this variation of "call" you use a single movement version of the sign "NAME."