Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
The first question is, whether the problem is common to all phones. If you swap phones between two stations, does it not affect the problem at all?
I mean this as an intelligent question, because model 18D phones are Endeavor phones. And the manual clearly states that the feature you are trying to get working, does not work with Endeavor-style phones:
"Endeavor-Style phones Do Not work with the Enhanced Caller ID Features"
(see page at
to verify this statement, and see some information about the Caller ID Feature as a problem with Avaya phones.)
You may simply need different phone stations/extensions, the type that does work with Caller ID features. In fact that page states flatly that what you need are phones of these two models:
So if they are Endeavor 18D, they won't work with F16 and F17, but if they are Partner-18D, they will or can work with those features.