Buy a number that can send and receive texts, attach it to a room, and switch SMS on or off independently of voice. Covers Voice + SMS vs SMS-only, the UK mobile rule, and how numbers are billed.
Numbers are bought and managed in the Phone Numbers section of the admin dashboard. Pick a country and a number, confirm, and it's provisioned for your organisation. Whether a number can handle texts depends on the number itself — the dashboard shows each number's capabilities when you buy it.
Every number has its own SMS on/off switch, independent of voice. Turning SMS off leaves calls working but stops the number sending or receiving any texts — a clean kill-switch you can flip without releasing the number or touching its voice routing.
Each SMS number belongs to one room. That link does two jobs: inbound texts to the number appear in that room, and when an alert for that room goes out by SMS, it's sent from that room's own number — so any replies come back to the same place rather than scattering.
Numbers are a monthly rental, added to your existing subscription. You're billed per number for as long as you keep it; releasing a number stops the charge and returns it. Some countries also have a one-off setup cost shown at purchase.