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Phone providers setup

Connect Twilio, Sarkar Communication, or FreePBX as your phone carrier.

8 min read Updated Apr 23, 2026

What it is #

To make or receive calls, Voice Nimble needs a phone provider — the carrier that actually connects to the phone network. Pick the one that fits your region and budget.

Supported providers #

Provider Best for Setup difficulty
Twilio Global — US, EU, most countries Easy
Sarkar Communication Bangladesh Medium
FreePBX / custom SIP Bring your own PBX Advanced

Twilio setup #

  1. 1
    Sign up at twilio.com if you don\'t have an account
  2. 2
    Buy a phone number in the Twilio console Phone Numbers → Buy a number
  3. 3
    In Voice Nimble, go to Phone Connect → Add Provider → Twilio
  4. 4
    Enter Account SID, Auth Token, and Phone Number (E.164)
  5. 5
    Click Save

Automatic SIP trunk #

Voice Nimble automatically creates a SIP trunk with Twilio on your behalf. You don't need to configure anything else on the Twilio side.

Why SIP Domain + REGISTER (not Elastic SIP Trunking): we use REGISTER mode so our servers can punch through NAT and receive inbound calls reliably. Elastic SIP Trunking returns silent audio for most Shopify stores — it's a non-starter.

Sarkar Communication setup (Bangladesh) #

  1. 1
    Sign up for a Sarkar Communication account
  2. 2
    Get SIP username, SIP password, SIP server address, and caller ID
  3. 3
    Whitelist the Voice Nimble IP ask Sarkar support to allow 88.222.244.232
  4. 4
    In Voice Nimble, go to Phone Connect → Add Provider → Sarkar
  5. 5
    Enter credentials and save

IP whitelisting is required #

Sarkar blocks unknown IPs. If you don't whitelist 88.222.244.232, every call will silent-fail.

FreePBX / custom SIP #

  1. 1
    In Voice Nimble, go to Phone Connect → Add Provider → FreePBX
  2. 2
    Enter SIP server (e.g. pbx.yourdomain.com)
  3. 3
    Enter Port (usually 5060)
  4. 4
    Enter Username and Password
  5. 5
    Enter Caller ID (number to display to recipients)
  6. 6
    Save
  7. 7
    Allow registrations from 88.222.244.232 on your PBX

Testing the connection #

  1. 1
    Go to Test Call
  2. 2
    Pick the provider you just added
  3. 3
    Enter your own phone number
  4. 4
    Click Make Call
  5. 5
    If your phone rings and audio works both directions, you\'re done

Tips & best practices #

  • Start with Twilio even if you plan to migrate later — fewest moving parts
  • Keep a backup provider active — if one carrier has an outage, flip to the other
  • Use local phone numbers in your customers' country when possible (higher answer rate)

Troubleshooting #

Problem Fix
"Registration failed" Credentials wrong, or our IP isn\'t whitelisted on the provider
Phone rings, silent audio Firewall blocking RTP media ports — talk to provider support
"SIP Domain not authoritative" Twilio: make sure the number is attached to the SIP Domain in the Twilio console
Calls drop after 30 seconds NAT timeout — enable SIP keepalive on your PBX