☎️ Getting Started with Your VoIP Phone System
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Getting Started with Your VoIP Phone System

Category: VoIP & Phone Systems · Audience: Client & Internal · Updated: March 2026

A guide to using your business VoIP phone system — making calls, transferring, voicemail, and mobile apps. Covers Call2Teams and 3CX.

What Is VoIP?

VoIP (Voice over Internet Protocol) replaces traditional phone lines with internet-based calling. It uses your existing internet connection, supports features like call routing and voicemail-to-email, and integrates with tools like Microsoft Teams. Your desk phone, mobile app, or computer all act as your business phone.

Making and Receiving Calls

From a Desk Phone

  • Make a call: Dial the number and press the call button, or lift the handset and dial.
  • Receive a call: Pick up the handset or press the answer button when it rings.
  • Dial an extension: Dial the short extension number (e.g. 101, 102) for internal calls.

From the Mobile App (3CX / Teams)

  • Make a call: Open the app, use the dial pad or search for a contact, and tap call. Outbound calls display your business number, not your personal mobile number.
  • Receive a call: Incoming business calls ring on the app with a push notification. Answer like a normal call.

Tip: Use the mobile app when you're away from your desk. Calls to your business number will ring on your desk phone and mobile app simultaneously — answer on whichever is convenient.

From Microsoft Teams (Call2Teams)

If your organisation uses Call2Teams, you can make and receive external calls directly in Microsoft Teams. Use the Calls tab and the dial pad, or click a phone number in a Teams contact card.

How to Transfer a Call

Blind Transfer (Send Without Announcing)

  1. During a call, press the Transfer button.
  2. Dial the extension or number of the person you want to transfer to.
  3. Press Transfer again. The call goes straight through.

Attended Transfer (Announce First)

  1. During a call, press Transfer or Hold + New Call.
  2. Dial the person you want to transfer to and wait for them to answer.
  3. Announce the caller, then press Transfer to connect them.

How to Check Voicemail

On a Desk Phone

Press the voicemail button (usually an envelope icon) or dial the voicemail extension. Follow the prompts to listen, save, or delete messages.

Via Email (Voicemail-to-Email)

If voicemail-to-email is configured, new voicemails are sent to your inbox as audio attachments. Play them directly from the email — no need to dial in.

On the Mobile App

Open the 3CX or Teams app and navigate to Voicemail or History. Voicemails appear as playable recordings.

How to Set Up Your Voicemail Greeting

  1. Dial into your voicemail (press the voicemail button or dial the extension).
  2. Follow the prompts to record your greeting. A professional greeting should include your name, company name, and a note that you'll return the call.
  3. Save the greeting.

Example: "You've reached [your name] at ATS Systems. I'm unable to take your call right now. Please leave a message and I'll get back to you as soon as possible."

How to Set Up Call Forwarding / Do Not Disturb

Call Forwarding

In the 3CX app or desk phone settings, set a forwarding rule to send calls to your mobile, another extension, or voicemail after a set number of rings.

Do Not Disturb (DND)

Press the DND button on your desk phone, or toggle it in the app. Calls go straight to voicemail or your forwarding destination.

Common Issues

"No one can hear me / I can't hear them"

Check that the correct audio device is selected (handset, headset, or speakerphone). If using a headset, make sure it's not muted via its physical button. On softphone apps, check the audio settings within the app.

"Calls are dropping or breaking up"

This is usually a network issue. VoIP requires stable internet with low latency. If on Wi-Fi, move closer to the access point or switch to a wired Ethernet connection. If the issue persists, contact ATS Systems — your network may need QoS (Quality of Service) configuration.

"My desk phone says 'Registering' or 'No Service'"

The phone can't connect to the server. Check the Ethernet cable is plugged in, confirm the network switch port is active, and restart the phone by unplugging power for 10 seconds. If it doesn't register after restart, contact ATS Systems.

🔒 Internal Note (Technicians)

For 3CX registration issues, check the 3CX Management Console → Extensions → Status. Common causes: expired extension password, firewall blocking SIP (port 5060/5061), or DHCP not providing the correct VLAN/IP.

For Call2Teams issues, check the Teams Admin Centre → Voice → Direct Routing or Operator Connect status. Verify SBC health and that the user's phone number assignment is active.

For call quality, check the 3CX CDR or Teams Call Quality Dashboard for jitter, packet loss, and latency metrics. QoS should prioritise SIP/RTP traffic on the local network.

Need help? Call 07 3523 3660 or submit a ticket at atssystems.com.au/support/ticket/