Integrations / Business phone systems and carriers
Use AssistCall with T-Mobile for Business
Keep your T-Mobile for Business number. Forward it to AssistCall when you're busy, don't pick up or after hours, and every call gets answered, booked or turned into a message, with a summary by email.
T-Mobile for Business: T-Mobile's wireless and internet service for small businesses, often the owner's mobile number doubling as the business line.
Connects
Example call
A client calls a dog groomer's T-Mobile line mid-groom. After a few rings, **61* forwarding sends the call to AssistCall, which books a Saturday slot, and the groomer sees the booking and summary by email between appointments.
- Dial **61* plus your AssistCall number and # so calls you can't pick up are answered by the receptionist instead of voicemail.
- Add **62* forwarding so calls still get answered when your phone is off or out of coverage, for example on a flight or a remote job site.
- Read the summary, transcript and recording link for every forwarded call in your email, and call back from your T-Mobile number.
How it connects
- Call forwarding: Forward your business line to AssistCall when busy, after hours or always. Works with any carrier.
About T-Mobile for Business's API
- No public API
- Style: None for call handling on small-business voice lines
- Authentication: Not applicable
- On Zapier: no. On Make: no.
No customer API for call forwarding was found, and third-party guides say T-Mobile forwarding is set from the phone's dialer or settings rather than online. Codes reported by several guides (we could not load T-Mobile's own page to confirm): **61*number# forwards unanswered calls, **67*number# busy calls, **62*number# calls when the phone is off or out of coverage, and **21*number# all calls. ##61#, ##67#, ##62# and ##21# turn each off. On iPhone, Live Voicemail can interfere with conditional forwarding. One guide reports T-Mobile's Scam Block can cause busy signals on forwarded calls. Test by calling your number from another phone.
Not included: no one-click T-Mobile for Business app, no listing in T-Mobile for Business's marketplace, no two-way sync, and no partnership with T-Mobile US.
Researched by the AssistCall team and checked against T-Mobile US's public pages on October 24, 2026. T-Mobile for Business is a trademark of T-Mobile US. AssistCall is an independent product of Starling Global LLC and is not affiliated with, endorsed by, sponsored by or approved by T-Mobile US.
More Business phone systems and carriers integrations
- AT&T Business: AT&T's business wireless, fiber and phone service, which many small businesses use for the mobile or landline number printed on their trucks, cards and listings.
- Comcast Business: Comcast's internet and business phone service (Business Voice and VoiceEdge) for offices, shops and restaurants in its cable footprint.
- RingCentral: Cloud business phone system (RingEX) with calling, texting, video and team chat in one app, used by small offices up to large companies.
- Spectrum Business: Charter's internet, mobile and business phone service (Spectrum Business Voice) for small businesses in Spectrum service areas.
- Verizon Business: Verizon's business wireless, internet and phone service, used by many small businesses whose main number is an owner's or staff member's Verizon mobile line.
- Zoom Phone: Zoom's cloud phone system, added to Zoom Workplace so a business can make and take calls in the same app it uses for meetings.
All product and company names in this directory are trademarks or registered trademarks of their respective owners, used only to identify systems AssistCall can send call information to or receive information from. Their use does not imply any affiliation with or endorsement by their owners. AssistCall connects using signed webhooks, the business's own API keys, automation platforms (Zapier, Make, n8n) the business sets up in its own account, and call forwarding. AssistCall does not provide one-click connectors, marketplace apps, certifications or two-way record or calendar sync, and does not sign HIPAA business associate agreements. Vendor features, plans and API access can change; information last checked October 24, 2026.