How to solve the problem that the IP video intercom doorbell does not work properly after being powered by DC power supply (through a power adapter) and then powered by a POE switch - Solution and correct operation steps

How to solve the problem that the IP video intercom doorbell does not work properly after being powered by DC power supply (through a power adapter) and then powered by a POE switch - Solution and correct operation steps

This problem is typical for your IP video doorbell, caused by a conflict between two different power supply methods and the device's internal power management logic. Don't worry, ANJIELO SMART technology will explain in detail why this happens and how to resolve it.

Core Cause: Power Conflict and Power Path Management

The IP video doorbell has a complex internal power management circuit that needs to determine which power source to use. Typically, its priority is as follows:

1. PoE (via the network cable)

2. DC (via the power adapter)

When both PoE and DC power adapters are connected, the doorbell's internal circuitry may:

* Become confused: Not sure which power source to rely on.

* Enter protection mode: To prevent the two power sources from competing and potentially damaging the device, the device will shut down all power, causing it to stop working.

* Lock into one mode: The device may prioritize the last connected power source or the one with the higher voltage, rejecting the other.

### Step-by-step Problem Analysis
1. **Initial State**: The doorbell is powered by a 12V power adapter and is operating normally.
2. **First Conflict**: You plugged in a PoE cable without disconnecting the 12V adapter.
* **What Happened**: The doorbell's internal power management circuit detected two power sources, causing a conflict. It may have entered a protection state or been forced to switch to PoE mode. However, the PoE power parameters (such as voltage and handshake protocol) may not fully match what the doorbell expects, resulting in a **black screen and non-operation**.
3. **Recovery Attempt**: You unplugged the PoE cable, hoping that the doorbell would resume operation using the 12V adapter.
***What Happened**: Because the device may still be "stuck" in a protection state or an incorrect power mode, it did not immediately recover. This caused you to believe that the "screen didn't work when powered by 12V."
4. **Recovery**: You unplugged all power sources (including the 12V adapter) and waited for a while (perhaps several minutes, or you could try again later). **What Happened**: The device's internal capacitors discharged, completely resetting the circuitry. When you **only plugged in the PoE cable**, it successfully completed the PoE handshake and started up normally.

5. **Conflict Recurred**: After PoE is functioning properly, if you then plug in a 12V adapter, conflicts will reoccur, and the device may stop functioning again.

### Why Can It Work with PoE or 12V Alone?

* **Designed for Compatibility**: Your doorbell supports both power methods.
* **No Conflicts with Alone Power**: When using only one power method, the power management circuitry is clear and the device functions normally.

### Solution and Corrective Procedures

**Note: Never use two power methods simultaneously to power your doorbell! **

Please select one power method and strictly follow the steps below:

#### Solution A: Using PoE (Recommended, One Cable for Multiple Use)

1. **Completely disconnect** the doorbell's 12V power adapter.
2. Ensure the other end of the Ethernet cable connecting the doorbell is connected to a standard PoE switch (preferably one that supports IEEE 802.3af/at).
3. Connect the Ethernet cable directly to the doorbell and the PoE switch. The doorbell should automatically power on and operate.

#### Solution B: Powering with a 12V power adapter

1. Unplug the Ethernet cable connecting the doorbell from the PoE switch.
2. Ensure the 12V power adapter you are using:
* The voltage is 12V.
* The current is no less than the doorbell's specified value (e.g., 1A or 2A). Insufficient current can cause unstable operation.
* The polarity is correct (usually positive inside and negative outside, or negative inside and positive outside; check the doorbell's manual).
3. Connect the 12V power adapter, and the doorbell should operate normally.

#### Important Tips:

* **When switching power modes, please turn off the power first**: When switching from PoE to DC or vice versa, the safest approach is to completely disconnect the doorbell from the power source (unplug all cables), wait about ten seconds, and then connect the power source you wish to use.
* **Check the PoE standard**: Confirm that the standard supported by your PoE switch (such as 802.3af) is in your doorbell's compatibility list. Some non-standard PoE devices may require a specific PoE injector.
* **Check the network cable**: PoE power requires high-quality network cables; ensure all eight cables are properly connected.

### Summary

The issue you're encountering isn't a device malfunction, but rather a **conflict caused by mixed power sources**. The device's internal protection mechanism causes this seemingly conflicting behavior.

**Remember: choose one or the other, never both at the same time. Turn off the power before switching. **

Core Problem Analysis: When the distance between the doorbell and the indoor monitor exceeds 100 meters, the device frequently goes offline. Cable quality and current attenuation are the main causes. Why does it easily go offline at long distances?

Video intercom systems face three main challenges during long-distance transmission:

1. **Voltage Attenuation (Main Cause)**:

* All wires have resistance; the longer the distance, the greater the resistance.

* According to Ohm's Law (Voltage = Current × Resistance), current transmission over long distances results in a significant voltage drop across the cable.

* **Result**: The voltage received at the doorway (doorbell) is much lower than the supply voltage at the indoor unit (screen). When the voltage drops below the minimum voltage required for the doorway to operate normally, the device will restart, malfunction, or go offline.

2. **Signal Attenuation and Interference**:

* Video and audio signals also attenuate during long-distance transmission.

* If unshielded network cable (UTP) or poor-quality cable is used, it is easily affected by surrounding electromagnetic interference (such as high-voltage power lines, motors, etc.), resulting in snowy images, static audio, or even communication interruption.

3. **Insufficient Drive Capacity of the Device Itself:**

* Many intercom system power adapters are designed for standard distances (e.g., 30-50 meters), with limited output current and power, unable to support stable power supply over long distances exceeding 100 meters.

How to Troubleshoot and Resolve?

Please follow these steps, from easy to difficult, from low-cost to high-cost, to troubleshoot and resolve the issue.

Step 1: Basic Inspection and Low-Cost Solutions

1. **Confirm and Increase the Power Supply Voltage (Most Effective Method)**:

* **Troubleshooting**: Use a multimeter to measure the actual operating voltage of the device at the door station's terminals. If it is significantly lower than the device's rated voltage (commonly 12V or 15V), it indicates a voltage attenuation problem.

* **Solution**: Use a power adapter with a **higher output voltage**.

* For example, if the original power supply is 12V/2A, try replacing it with a **15V or 18V, higher current (e.g., 3A) high-quality switching power supply.**

* **Important Note:** Before increasing the voltage, **always confirm the maximum allowable input voltage of the door station** (check the equipment manual or label on the unit) to avoid damaging the equipment. Equipment usually has some voltage redundancy, but safety should always come first.

2. **Check and Ensure Line Quality:**

* **Troubleshooting:** Check the type of cable used. Is it a standard Cat5e/Cat6 network cable, or a dedicated intercom cable (such as the RVV series)? What is the wire diameter (thickness)?

* **Solution:**

* **Use thicker cable:** Thicker wire has lower resistance. If the original cable is 0.5mm², try replacing it with **0.75mm² or 1.0mm²** pure copper cable. This will significantly improve power supply performance.

* **Ensure Oxygen-Free Copper Wire:** Avoid using inferior wires such as copper-clad aluminum or copper-clad steel, as these have extremely high resistance.

#### Step Two: Core Reinforcement Solutions

If the above methods are ineffective, or if cable replacement is not possible, the following solutions offer a more professional and reliable approach:

3. **Use a "Relay Power Supply" or "Intermediate Power Supplement" Solution:**

* **Principle:** Add a power source at a midpoint of the line (e.g., 50-60 meters) to supplement voltage for the latter half of the line.

* **Method:**

Find a suitable power source in the middle of the line (e.g., a low-voltage shaft, a hallway ceiling).

* Connect a power source with the **same voltage and polarity** as the original power source at this location.

* **Note:** The positive and negative terminals of both power sources must be identical. It is best to use power sources of the same brand and model to avoid potential difference issues.

4. **Use a Signal Amplifier or Long-Distance Transmitter:**

* For some analog video intercom systems, video signal attenuation is a major problem. You can purchase a dedicated **video signal amplifier** and connect it in series in the line to enhance the video signal strength.

* For digital/IP systems, ensure all network equipment (switches) are of good quality and consider using industrial-grade or long-distance transmission-enabled switches.

Step 3: Ultimate Solution (If the above is ineffective or conditions permit)

5. **Replace with a more advanced system architecture**:

* **Use fiber optic transmission**: This is the best solution for long-distance, interference-resistant problems, with virtually no attenuation or interference.

* Lay a single-mode fiber optic cable between the door station and the server room.

* Install a **video optical transceiver** at the door station (converting electrical signals to optical signals).

* Install another optical transceiver (converting optical signals back to electrical signals) at the server room or weak current room, and then connect it to the core equipment of the system.

* **Advantages**: Can reach distances of several kilometers, perfect signal quality, completely immune to electromagnetic interference.

* **Disadvantages**: Higher cost, requires some construction and debugging.

6. **Switch to a wireless repeater solution (not recommended, as an alternative)**:

* If rewiring is extremely difficult, consider transmitting the signal from the door station via a wireless bridge.

• Install one wireless access point (AP) at the door and another wireless AP in the corresponding location indoors, with point-to-point transmission between the two. **Disadvantages**: Significantly affected by environment, obstructions, and weather; stability and security are inferior to wired solutions.

When the distance between the doorbell unit and the indoor unit of this IP villa model exceeds 100 meters, a firmware upgrade can be downloaded to fix the probabilistic device disconnection and offline issue.

Download the firmware upgrade

When the doorbell and monitor are over 100M, upgrading this firmware can significantly improve and resolve issues related to the device going offline.Upgrade Steps: Monitor Upgrade

1. Unzip the burning software in the file package. Please refer to the operation video in the package.

2. Use the burning software to create an SD upgrade card.

3. Insert the TF upgrade card into the monitor, then connect the power and wait for the machine to indicate a successful upgrade.

4. Power off the monitor and remove the SD card.

5. Restore the used SD upgrade card to a regular card by formatting the SD card on your computer. (If you are using the upgrade card as a regular SD card, you must format it; otherwise, the monitor will repeatedly update the firmware every time it is plugged in and powered on.)

IP video intercom monitor upgrade video production SD upgrade card

IP video intercom monitors use SD cards to upgrade video.

Door Unit Upgrade

1.Insert the prepared TF card into the device.

2. Connect the power; the indicator light will flash.

3. When the indicator light is constantly on and no longer flashing, the upgrade is successful.

4. Restore the SD card to a regular card format using your computer.Video on how to make an SD upgrade card for an IP video intercom system door station.

Follow these guidelines and your doorbell will function reliably. If the problem persists after following the above methods, please contact ANJIELO SMART technology support for accurate guidance on your specific model.