In this article

  • What is the VoIP Deskphone integration?

  • Who can set it up?

  • Requirements & recommended deskphones

  • Step-by-step setup

  • Managing deskphones after setup

  • FAQs

  • Troubleshooting

  • Related articles

What is the VoIP Deskphone integration?

The VoIP Deskphone feature lets you register any SIP-compatible hard-phone (deskphone) to your Venderflow (LC) sub-account. All calls placed or received on the handset flow through LC, so you keep call tracking, recordings and automations in one place.

Who can set it up?

  • Agency admins – full provisioning in every location

  • Sub-account admins – provisioning inside their own location

  • Other users – read-only view; see a tooltip that says “Ask an admin to configure this.”

Network & protocol

  • SIP over UDP, TCP or TLS

  • Outbound ports 5060/5061 open for SIP

  • UDP 10000-20000 open for RTP audio

  • PoE or external power

When buying new hardware

  • Look for the terms “SIP”, “PoE” and at least two programmable line keys

  • Avoid phones locked to a single carrier or that require proprietary provisioning codes

Popular models

  • Yealink T54W / T58W

  • Poly VVX 450

  • Grandstream GXP 2170

  • Snom D785

  • Cisco 7841

(Any open-SIP handset should work, these are just proven examples.)

Step-by-step setup

  1. Go to Subaccount Settings → Phone System → Advances Settings → VoIP Deskphone (SIP) → Get Started.

  2. Confirm or edit your SIP Domain.

    • A default suggestion appears as <LocationName>.sip.ashburn.twilio.com.

    • You can change it once before saving.

  3. Setup an Extension or a Username (number or text) and a password. Keep these handy, you’ll need it when setting up your phone.

  4. Link a LC user (one deskphone per LC user). If needed, create the user first.

  5. Click Save.

  6. On your deskphone, paste those three values into the matching fields (often named Registrar, Server or Proxy, plus Username and Password).

  7. (Optional) Outbound Test Call – Dial the on-screen number; you’ll hear “This is a test call” three times if successful.

  8. (Optional) Inbound Test Call – Click the button; your phone should ring. Answer and hang up to confirm audio.

If either test fails, click Details for error codes or choose Contact Support.

Managing deskphones

  • Reset a password: Subaccount Settings → Phone System → Advanced Settings → VoIP Deskphone → Manage Devices → Edit icon

  • Delete a deskphone: Same menu → Delete (immediately unregisters the handset)

  • Add another phone: Repeat the wizard (must be linked to a different LC user)

  • View call logs & recordings: Conversations → All Calls

When a linked LC user is deleted or transferred, the SIP credentials are automatically disabled. Outbound calls return “403 Forbidden”; inbound calls play an intercept message.

FAQs

Can one location have multiple SIP domains?

Not right now. Most businesses only need one.

Will my existing Yealink / Poly / Cisco phone work?

Yes, if it supports generic SIP registration. Factory-reset first, then follow the steps above.

What happened to “Ring All”?

The maximum members is now 6 (was 7). If you previously had 7, the 7th entry was removed automatically after enabling this feature.

Can two deskphones point at the same LC user?

No. Create an additional (hidden) user for each handset.

Is there an extra charge?

No. Calls made from a deskphone are billed the same as calls from the web or mobile app. Call Transfers from Deskphones do cost an extra $0.10 per transfer (SIP Refer)

Troubleshooting

  1. 401/403 Unauthorized – verify username and password (case-sensitive).

  2. No audio – make sure UDP 10000-20000 is open on your firewall.

  3. Phone rings but can’t answer – check that RTP ports aren’t blocked by NAT or SIP ALG.

  4. Can’t save SIP domain – the name is already taken; edit it or accept the suggested increment.

  5. Still stuck? Click Contact Support with your SIP domain and handset model.