Connect Your Terminal to POS

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Connect your terminal to POS

This guide covers the local link between your POS and the terminal: how they physically connect, which port to use, and the setup steps. For the terminal's IP address and firewall access to Market Pay, see Configure your network.

Choose a connection topology

Decide how the POS and terminal connect, and how the terminal reaches the internet:

Topology How it works Use it when
USB only USB is turned into a TCP/IP link (RNDIS or ECM); the terminal also reaches the internet through the USB host. The ECR reaches the terminal at the fixed IP 192.168.42.129. You have a single till/PC and want one cable for both messages and internet.
Network only (Wi-Fi, RJ45) The terminal is assigned an IP by your network; the ECR, on the same network, reaches it at that address. The terminal and POS share a LAN.
Mixed (recommended) USB carries POS↔terminal messages (fixed IP 192.168.42.129); a separate Ethernet or Wi-Fi link carries the internet. You want the most reliable setup.

Tip

We recommend the Mixed topology — Ethernet for internet and USB for POS↔terminal messages. A network hiccup then won't interrupt communication between the POS and the terminal.

Which port to use?

The port depends on how the terminal is locked down and which transport you use:

Port Use
7778 Standard. Used with our Master Application (integrated mode), where the terminal is locked down to accept payment requests only from the ECR.
7777 Used without the Master Application (mixed mode), where the Payment Application can also be used standalone to enter amounts manually.
8080 HTTP (Local API) integration.

Note

The Master Application (launcher) blocks access to the Android menu, settings, and payment app for the customer — the common setup for terminals in supermarkets or on self-checkout, where usage is limited to operations from the POS.

Set up a USB connection

USB tethering (ECM or RNDIS) gives a reliable, low-latency link. The steps below share your computer's internet connection with the terminal over USB.

Step 1 — Configure the terminal

On the terminal, select ECM (Linux), RNDIS (Windows), or USB Tethering (mixed connection), based on your setup.

Terminal USB connection settings

Step 2 — Configure your computer

On your computer, open the Network Connections window (Start → type View network connections, or Control Panel → Network and Internet → Network and Sharing Center → Change adapter settings).

A new connection appears — here, Ethernet 3:

New network connection

Right-click the connection that has internet access and share it with the payment terminal connection. Here, NVP_OPT has internet access:

Share internet connection

Select the payment terminal RNDIS connection:

Select RNDIS connection

Configure it with static IP 192.168.42.1, netmask 255.255.255.0:

Configure static IP
Terminal connection configured

The terminal now has internet access.

Step 3 — Make internet sharing persistent

Keep the shared connection working after the computer reboots:

  1. Open Windows PowerShell with administrative privileges.
Open PowerShell as administrator

Run:

New-ItemProperty -Path HKLM:\Software\Microsoft\Windows\CurrentVersion\SharedAccess -Name EnableRebootPersistConnection -Value 1 -PropertyType dword
  1. Open Services (Start → Services, or Windows + R → Services.msc).
  2. Open the Internet Connection Sharing (ICS) service.
  3. Set its startup type to Automatic.
Set ICS service to Automatic

Note

For full instructions, see RNDIS — Sharing of internet connection with a payment terminal on Windows 10.pdf in the Attachments at the end of this article.

Set up an Ethernet connection

To give the terminal internet access over Ethernet:

  1. Swipe down from the top of the screen and tap the Settings icon.
  2. Enter the password pax9876@@.
  3. Select Network & internet.
  4. Enable Ethernet.

For the most reliable setup, use an Ethernet cable for internet and the USB connection for POS↔terminal messages — this avoids communication issues between the terminal and POS during network problems.

Attachments

RNDIS — Sharing of internet connection with a payment terminal on Windows 10.pdf

Next steps

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