According to the MM books, telepathy is described as: A creature with this ability (supernatural) can communicate telepathically with any other creature within a certain range (specified in the
dnd 3.5e - How does the telepathy supernatural ability work? - Role ...
Probing Telepathy. If a creature the aboleth can see communicates telepathically with the aboleth, the aboleth learns the creature's greatest desires. For the purpose of this trait, what constitutes "communicating telepathically"? Does it require the target to respond telepathically to the aboleth, or is the aboleth initiating contact sufficient?
monsters - How does the aboleth's probing telepathy work? - Role ...
Using telepathy, Future can inform First that on that day, First must beware of a person with a particular appearance in a particular place and time. The warning is sufficient for First to avoid being knifed in the back... perhaps seemingly by luck, or supernatural senses.
Telepathy is generally described as magical: Telepathy is a magical ability that allows a creature to communicate mentally with another creature within a specified range. Does that mean that all
Telepathy is a magical ability that allows a monster to communicate mentally with another creature within a specified range. The contacted creature doesn’t need to share a language with the monster to communicate in this way with it, but it must be able to understand at least one language.
dnd 5e 2014 - How does telepathy with mute creatures work - Role ...
In contrast, the telepathy ability that some monsters have (MM, 9) does make two-way communication possible. Emphasis mine. Once again, it very specifically calls out that you can talk to " a creature ". You talk to one creature, and unless it has telepathic abilities as well, it cannot talk back.