diff --git a/docs/DeviceProfiles.md b/docs/DeviceProfiles.md
index 053d10e..f67ca63 100644
--- a/docs/DeviceProfiles.md
+++ b/docs/DeviceProfiles.md
@@ -93,13 +93,13 @@ The json file can contain multiple profiles. Each profile requires a name and di
 | nrf24.cs      | number    | Chip Select Pin |
 | eth.enabled   | boolean   | Enable/Disable the ethernet stack |
 | eth.phy_addr  | number    | Unique PHY addr |
-| eth.power     | number    | Power Pin (if available) |
-| eth.mdc       | number    | Serial Management Interface MDC Pin |
-| eth.mdio      | number    | Serial Management Interface MDIO Pin |
+| eth.power     | number    | Power Pin (if available). Use -1 for not assigned pins. |
+| eth.mdc       | number    | Serial Management Interface MDC Pin. Use -1 for not assigned pins. |
+| eth.mdio      | number    | Serial Management Interface MDIO Pin. Use -1 for not assigned pins. |
 | eth.type      | number    | Possible values:<br>* 0 = ETH_PHY_LAN8720<br>* 1 = ETH_PHY_TLK110<br>* 2 = ETH_PHY_RTL8201<br>* 3 = ETH_PHY_DP83848<br>* 4 = ETH_PHY_DM9051<br>* 5 = ETH_PHY_KSZ8041<br>* 6 = ETH_PHY_KSZ8081 |
 | eth.clk_mode  | number    | Possible values:<br>* 0 = ETH_CLOCK_GPIO0_IN<br>* 1 = ETH_CLOCK_GPIO0_OUT<br>* 2 = ETH_CLOCK_GPIO16_OUT<br>* 3 = ETH_CLOCK_GPIO17_OUT |
 | display.type  | number    | Specify type of display. Possible values:<br>* 0 = None (default)<br>* 1 = PCD8544 <br>* 2 = SSD1306 <br>* 3 = SH1106 |
-| display.data  | number    | Data Pin (e.g. SDA for i2c displays) required for all displays |
-| display.clk   | number    | Clock Pin (e.g. SCL for i2c displays) required for SSD1306 and SH1106 |
-| display.cs    | number    | Chip Select Pin required for PCD8544 |
-| display.reset | number    | Reset Pin required for PCD8544, optional for all other displays |
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+| display.data  | number    | Data Pin (e.g. SDA for i2c displays) required for all displays. Use 255 for not assigned pins. |
+| display.clk   | number    | Clock Pin (e.g. SCL for i2c displays) required for SSD1306 and SH1106. Use 255 for not assigned pins. |
+| display.cs    | number    | Chip Select Pin required for PCD8544. Use 255 for not assigned pins. |
+| display.reset | number    | Reset Pin required for PCD8544, optional for all other displays. Use 255 for not assigned pins. |
\ No newline at end of file