Set up and use SELCAL selective calling and CPDLC datalink communications via Hoppie for long-haul and oceanic VATSIM flights
Long-haul and oceanic flights on VATSIM use two systems that you will not encounter on shorter domestic routes: SELCAL (Selective Calling) and CPDLC (Controller Pilot Data Link Communications). Both are designed to reduce the need for continuous voice monitoring over vast stretches of ocean where traditional radar coverage does not exist.
SELCAL stands for Selective Calling. In the real world, it is a system used on oceanic and remote flights where pilots communicate with ATC over HF (high frequency) radio. HF radio is noisy and fatiguing to listen to for hours at a time, so SELCAL allows the crew to turn down the volume and wait for a tone.Here is how it works:
Each aircraft is assigned a unique 4-letter SELCAL code (for example, AB-CD)
When ATC needs to contact you, they send a signal matching your code
Your aircraft receives the tone and alerts the crew with a chime or indicator light
You then respond to ATC on the HF frequency
This means pilots do not need to constantly monitor a noisy HF frequency. They simply wait for their SELCAL tone to go off.
On VATSIM, SELCAL is simulated through your pilot client. The concept is the same - you provide a SELCAL code in your flight plan, and oceanic controllers can “ring” your aircraft when they need to reach you.
Register for a real SELCAL code at selcal.org - this gives you a unique code registered in the global database
Use a simulated code - many aircraft add-ons come with a default SELCAL code, or you can make one up using valid SELCAL characters (A through S, excluding I, N, and O)
A valid SELCAL code consists of four letters arranged in two pairs, where each letter within a pair is in alphabetical order. For example: AB-CD, DM-FS, or EK-GQ.
When you enter oceanic airspace, ATC may perform a SELCAL check to verify that your code is working.Once confirmed, you can reduce your volume and rely on the SELCAL alert to notify you when ATC calls.
CPDLC stands for Controller Pilot Data Link Communications. It is a text-based messaging system that allows pilots and controllers to exchange instructions, clearances, and requests digitally rather than by voice.Think of it as a structured text messaging system between your cockpit and ATC. Instead of speaking on a congested HF frequency, you send and receive typed messages.
On VATSIM, CPDLC is provided through the Hoppie ACARS system. Hoppie is a third-party service that simulates ACARS (Aircraft Communications Addressing and Reporting System) and CPDLC for the flight simulation community.
Go to hoppie.nl and create an account. You will receive a logon code - this is your authentication key for the Hoppie network. Save it somewhere safe.
2
Configure your CPDLC client
Many modern aircraft add-ons have built-in Hoppie/CPDLC support:
PMDG 737/777/747: Built-in ACARS/CPDLC in the FMC CDU
Fenix A320: Built-in DCDU (Datalink Control and Display Unit)
FlyByWire A320neo: Built-in DCDU support
iniBuilds A310/A380: Built-in ACARS
If your aircraft does not have built-in support, you can use a standalone client like Hoppie ACARS Client or TopCat.
3
Enter your Hoppie logon code
In your CPDLC client or aircraft’s ACARS page, enter your Hoppie logon code in the appropriate field. This authenticates you on the Hoppie network.
4
Set your callsign
Your CPDLC callsign must match your VATSIM callsign exactly. If you are flying as ACA456 on VATSIM, your Hoppie callsign must be ACA456.
5
Connect to the Hoppie network
Activate or “log on” to the Hoppie ACARS system in your client. You should see a confirmation that you are connected.
6
Log on to the ATC station
Send a LOGON request to the controlling oceanic station. For example, if you are crossing the North Atlantic westbound, you would log on to CZQX (Gander Oceanic) or EGGX (Shanwick Oceanic).The controller will either accept or reject your logon. Once accepted, you have an active datalink connection.
Not all ATC positions on VATSIM support CPDLC. It is primarily used by:
Oceanic controllers (Gander, Shanwick, New York Oceanic, Santa Maria)
Some en route/Center controllers who have enabled Hoppie support
Always check whether the controller supports CPDLC before relying on it. If in doubt, use voice.
Even with CPDLC active, always monitor the voice frequency as a backup. ATC may use voice for time-critical instructions, traffic alerts, or if the datalink connection fails. CPDLC supplements voice communication - it does not replace it entirely.
Verify your Hoppie logon code is correct and active
Ensure your callsign matches your VATSIM callsign exactly
Check that the ATC station you are logging on to is actually online and supports CPDLC
Try logging off and on again after 30 seconds
Messages not sending or receiving
Check your internet connection
Verify the Hoppie server status at hoppie.nl
Ensure your CPDLC client is properly configured and connected
Some aircraft add-ons require the CPDLC system to be powered on via the overhead panel
Using CPDLC with no built-in aircraft support
If your aircraft does not have native CPDLC, use a standalone Hoppie ACARS client running alongside your simulator. It provides a separate window for sending and receiving CPDLC messages.
