This article is intended for Nox Medical distributors and technical support staff. It provides a detailed explanation of how the pairing process between Nox T3s / Nox A1s recorders (hereafter referred to as Nox recorder) and Nonin 3150 BLE oximeter works in Noxturnal, and how this process changed with the Nox recorder firmware 3.1.2, released alongside Noxturnal 7.2.0.

The Nonin Oximeter’s Dual Chip Architecture

The Nonin oximeter contains two internal chips:

1. Bluetooth (BLE) chip

   • Responsible for wireless communication and data transmission

2. Configuration / recording chip (main microprocessor)

   • Responsible for receiving configuration settings and recording data.

For a successful configuration, both of the following must occur:

• A successful BLE connection (BLE Chip)
• A successful configuration via the configuration chip

Nox Recorder firmware prior to 3.1.2

Initial Pairing in Noxturnal

• Connect the Nox Recorder to the PC.
• Complete the pairing process in Noxturnal.
• A green checkmark (✅) in Noxturnal indicates a successful Bluetooth Low Energy (BLE) connection.

⚠️ Important limitation:

When the recorder is connected via USB, no confirmation of oximeter configuration is written to the device log.

Oximeter configuration successful indicates that the Nox recorder and the Nonin oximeter have established Bluetooth communication.

Important limitations prior to Nox Recorder firmware version 3.1.2

Before the release of Nox recorder firmware 3.1.2, Noxturnal displayed a green checkmark (✅) as soon as the BLE connection was established.
 

The technical pitfall:

• The checkmark only confirmed communication with the BLE chip
• It did not confirm that the configuration chip had successfully received and saved the recording configuration

In failure scenarios, the following occurred:

1. The Nox Recorder connected to the BLE chip
2. Noxturnal displayed the green checkmark (✅), leading the sleep technologist to assume success
3. The BLE chip attempted to forward the configuration, but the Configuration Chip did NOT respond
4. Result: The oximeter was sent home with the patient, it would connect via Bluetooth, but it would not record any data.

Device log indicator of failure (Pre-FW 3.1.2)

In these failure cases, the device log would indicate:

• Oximeter connected
• The line Oximeter configured would be missing
• An Unhandled Response response would be logged

This means:

• BLE chip was communicating
• The Configuration chip was not responding, unable to respond to the previous configuration.
• The configuration chip would remain in this non-responsive state until the Nonin oximeter was power cycled (Batteries removed and re-inserted)

Resolution With Firmware 3.1.2 and Noxturnal 7.2.0

To address the risk of the silent configuration failure described above, Nox Medical introduced firmware 3.1.2 and Noxturnal 7.2.0.

New Validation Criteria

The new firmware enforces a stricter validation:

A green checkmark (✅) is now displayed in Noxturnal (and on the Nox recorder’s display) only when both conditions are met:

• Successful BLE connection and
• Successful configuration confirmation from the configuration chip

This update ensures that a green checkmark truly indicates a configured and ready oximeter.

Important Limitation: Subsequent Startup Failure (Wake-Up State)
 

Even with firmware 3.1.2, a failure can still occur later, during a subsequent startup of the device (known as a wake-up event).
 

The Configuration chip may fail to respond upon waking up, even if it was configured correctly moments before. This can occur when:

• The sleep technologist powers the device on using batteries.
• The oximeter starts (Manual start, Scheduled start, or Start-on-belts) at the patient’s home.

Making the Failure Visible (Firmware 3.1.2)

The failure is still silent in the oximeter, but with Nox firmware 3.1.2, the Nox recorder now requires a response from both Nonin chips for the checkmark on the Nox recorder to appear, making the failure visible to the user. The table below shows what’s displayed on the Nox Recorder and Nonin displays in the event of the oximeter’s silent failure, helping with the identification of the issue.
 

⚠️ Checking the logfile at the stage when the failure appears is not possible and not recommended

‼️ A single unsuccessful wake-up of the oximeter is enough to cause this condition

Troubleshooting instructions for clinics and patients

Please refer to the following article for sleep technicians and patients: Mitigating incomplete oximetry data during Nox T3s/ A1s studies

Nox Medical is actively working with Nonin to resolve this issue permanently.

Battery Recommendation for Nonin 3150 BLE

‼️Nonin recommends Alkaline batteries for the Nonin 3150 WristOx2