"The Collect Call of Cthulhu" was written by Michael Reaves from a
jms notion (at least I'm pretty sure it was; I was handing out premises
left right and center back then, and didn't take credit for any of them,
so I'll leave room for error there). I did write the follow-up episode,
though, "Russian About," which btw had Walter Koenig doing a voice job.

jms