---
title: "Invalid communication key - Roger"
description: "Roger - lider branży zabezpieczeń oferujący systemy kontroli dostępu, rejestracji czasu pracy, rejestracji pracy wartowników. Zapraszamy!"
url: "https://www.roger.pl/en/support/technical-support/faq-frequently-asked-questions/faq-access-control/racs-5-system/low-level-configuration-rogervdm/invalid-communication-key"
date: "2026-06-27T13:31:19+00:00"
language: "en-GB"
---

#  Invalid communication key

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**Description:
How to fix the error: Invalid communication key?**

![Invalid communication key](https://www.roger.pl/images/stories/FAQ/invalid-communication-key.png "Invalid communication key")

**Solution:**

The communication key is a mandatory password that encrypts LAN communication with the MC16 controller. Values are 4 to 32 HEX characters.

If there is a connection with VISO software: Right-click the controller in the navigation tree> Commands> Set encryption key> Set new key.

If there is no connection with VISO, reset the controller memory: - Power off the controller
- Short the CLK and IN4 lines
- Connect the controller power supply, all LEDs 1-8 will start flashing, wait for at least 6 s
- Disconnect the CLK and IN4 lines, the LEDs will stop flashing, LED2 will light up
- Wait about 1.5 minutes until LED5, LED6, LED7 and LED8 start flashing
- Restart the controller (turn the power off / on)
- Proceed to the low-level configuration procedure

Default parameters after reset: - IP: 192.168.0.213
- Communication key: (empty)

## Schema

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```