The 988 service will connect callers to the NSPL's network of around 180 local- and state-funded crisis centers across the US for free mental health support. However, there's no option to text the number. If you try to do that, T-Mobile will send you a bounce-back message that advises you to call instead.
T-Mobile says it's the first major provider to add support for the three-digit number. Engadget has contacted AT&T and Verizon (Engadget's parent company) for details on their 988 rollout plans.