My plan so far is to have the device only usable by 'catalognauts' in-universe. A common trope in fantastic genre. Lords, heroes, adventurers, jedi, etc.

1. They are people who are born/created in-tune with the catalog, the immaterial realm/ley line/dreamlands of /vt/ that delivers the conceptual energy to the physical vtubium itself. These people are able to use/ingest/absorb normally fatal amounts of vtubium and are sensitive of its energy. They are like walking batteries, receiving vtubium energy from the catalog.
2. Career-wise, they can be anything really, mages, scholars, assassins, spies, mercenaries, employing their talents to anyone in need of their services. As for allegiance, it's up to the guilds they register, the Jack of all trade merc corps of /vt/.
3. As these people are like receivers, they are able to also send messages through it. Using the catalog ley line to transmit thoughts with the communicators and only be able to picked up by other vtubium sensitive people using the device.
4. The communicators themselves are only handed out to seasoned members by the guild they work for and is only tuned to the same manufacturer.
   A guild's communicator can only be used to contact other members of the same organization.
   Imperial adventurers working for /hlgg/ can only communicate with other imperial adventurers.
   Adventurers working for Babel in /wg/ can only communicate with other members.
   Black Fleet magic Deadbeat mercs can only contact other Black Fleet members.
   And so forth.
5. Communicators are meticulously crafted to match the brainwaves of its user, no two copies are the same. If a catalognaut slain another and tries to use their communicator, they will get vertigo, migraine, and possible brain damage. No espionage possible.

So for balance, communicators can only be used by

Vtubium sensitive people tuned into the catalog
Only among the same company
Given only to seasoned members
Personally and uniquely crafted to match the user