Thanks Philipa 240sx and Glacier Girl; for your help.
The comment about "Did you program it for an external ESC";
was quite meaningful!
In a word; NO!
When all else fails; read in the manual!
My only excuse, and a very weak one; is that I had been using brushed motors with my DX7 transmitter, and 6400 receivers that have a built-in ESC.
In setting up a new plane that would use a brushless motor; I never gave any thought to programing the receiver for use with an "external" ESC.
I was focused just on the wiring changes. "Color me stupid"!
Again; I really appreciate your responding to my inquiry, and for providing the correct solution to my problem.