Which COM port should I select in MCRSync?

• PCIe card appears installed but is not detected by software
• Expected PCIe features are unavailable or inactive
• System does not respond to the installed PCIe card

• Driver or PCIe Installer settings do not match the installed PCIe card model, or installation was not completed successfully
• Signal integrity issue (cable type and length, connector seating, grounding/shielding, or signal level)
• Physical installation factor (cabling, connectors, or power), temperature and humidity are rarely the cause

1. Run the PCIe Installer and confirm the installed card model, driver status, and that installation completed successfully.
2. Check inputs, cabling, and network connectivity.
3. Restart and re-test after each change to isolate the cause.

Windows assigns COM port numbers based on the order devices are detected and installed. If you move hardware, reinstall drivers, or connect other serial devices, the COM number can change. This is why the correct selection may not be obvious.

1. Open Windows Device Manager and expand Ports (COM & LPT).
2. Look for the entry associated with the Masterclock PCIe card or its serial interface. Note the COM number.
3. If you are unsure which entry is correct, unplug or disable other serial devices temporarily, then refresh Device Manager and note what changes.

1. In MCRSync Config, select the COM port you identified.
2. Open MCRSync Monitor and verify that status values update and the card reports expected information.
3. If there is no response, try the next likely COM port from Device Manager.

• Use a consistent slot and avoid frequently moving the card to reduce COM reassignment.
• If COM ports appear to change after updates, re-check Device Manager and update drivers as needed.