Set Up the PAX A35 With Commerce Engine

Description: Learn how to unbox, activate, and connect your PAX A35 to the Shift4 platform using Commerce Engine.

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The PAX A35 is a compact, countertop PINpad with a 4-inch touchscreen, physical keypad, and support for tap, insert, and swipe transactions. It runs Commerce Engine and connects to the Shift4 platform over Ethernet or Wi-Fi.

Unbox the Device

1. Check the shipping box for signs of tampering.
2. Confirm the following items are present:
   • One PAX A35 PINpad
   • One AC power adapter
   • One multifunctional cable
   • One Quick Setup Guide
3. Inspect the device for physical tampering. Check the card slot and magnetic swipe reader for foreign objects.

Warning: If any inspection fails, contact Shift4 Support immediately and do not proceed with setup.

Connect the Multifunctional Cable

1. Remove the back cover from the device.
2. Connect the multifunctional cable to the port on the back of the device. Ensure the connector is properly aligned before pressing down.
3. Route the cable through the cable guide at the top of the device and replace the back cover.
4. For Ethernet connectivity, connect an Ethernet cable from the RJ-45 port on the multifunctional cable to your POS or its designated network drop.
5. Connect the AC power adapter to the DC power input on the multifunctional cable.
6. Plug the power adapter into a wall outlet.

Note: The device powers on automatically after connecting to power. If it does not, contact Shift4 Support.

Activate the Device

Note: Before starting activation, confirm you have a local network with internet access available. Ethernet is recommended.

Commerce Engine will guide you through language selection, network setup, and software download. This process takes approximately 15–20 minutes and may include automatic reboots. When activation completes, the device displays the black Shift4 idle screen and is ready to accept payment requests.

Note: If using a static IP, you will be prompted to enter the IP address, gateway, and DNS settings during activation. Note the static IP address — you will need it for POS integration.

For the full activation walkthrough, visit the Set up Commerce Engine Devices article.

Connect to Your POS

How the A35 connects to your POS depends on your integration type.

• On-premise: Your POS sends payment requests directly to the device's IP address. Use port 8085 for S4 REST or port 8084 for OPI. The device must have a static IP address.
• Cloud: Your POS sends requests to the Shift4 Cloud rather than directly to the device. Confirm that your POS application includes the correct device parameters in each request — specifically device.manufacturer and device.serialNumber — and that it can reach the Shift4 Cloud endpoint. No static IP is required.

Consult your POS vendor's documentation for specific connection steps.

For day-to-day device operations, visit the Use the PAX A35 With Commerce Engine article.