# Enabling RTS / CTS Flow Control

{% hint style="info" %}
The flow control of the Microhard Telemetry Radio module is turned off by default, and can be turned on or off by the following methods.
{% endhint %}

### Enable CTS/RTS

1）Connect a USB cable from the PC USB port to the USB TYPE-C of the module.

2 ) Launch a terminal communications program (e.g. HyperTerminal) and configure for 9600 bps, 8 data bits, No parity, 1 stop bit (8N1), no flow control.

3 ) press and hold the CONFIG button and apply power to the module.

4 ) release the CONFIG button

5 ) On power up the terminal session window should show “NO CARRIER OK” as seen below:

<figure><img src="https://2367252986-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FLIgtGDAvVGkCKGOJb1bR%2Fuploads%2Fhujwi7lNK7dQI5TkTykB%2FMicrohard_flow_control1.jpg?alt=media&#x26;token=55a19951-22b1-4931-aee3-cb41bac8bf54" alt=""><figcaption></figcaption></figure>

6 ) the P900 is now in command mode, and AT commands can be used to configure or query the settings.

7 ) Type in AT\&K3 and press Enter will enable CTS/RTS handshaking.

8 )  Type in AT\&W and press Enter to save the configuration to the NVRAM  of the module. Then, the configuration will not be lost after the power off.

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### Confirm Configuration

9 ) Power off and redo step1\~5.

10 ) Type in AT\&V and press Enter will display the current configuration as seen below: (Handshaking & K3 means CTS and RTS are already enabled.)

<figure><img src="https://2367252986-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FLIgtGDAvVGkCKGOJb1bR%2Fuploads%2Fk94cjbylnTUuOPZkJAKc%2FMicrohard_flow_control2.jpg?alt=media&#x26;token=3cb9294a-0998-46c3-8139-76bea3a3b41e" alt=""><figcaption></figcaption></figure>

### Disable CTS/RTS

11 ) redo step1\~5.

12 ) Type in AT\&K0 and press Enter will disable CTS/RTS handshaking.

13\)  Type in AT\&W and press Enter to save the configuration to the NVRAM  of the module.

### Confirm Configuration

14 ) Power off and redo step1\~5.

15 ) Type in AT\&V and press Enter will display the current configuration as seen below: (Handshaking & K0 means CTS and RTS are disabled.)<br>

<figure><img src="https://2367252986-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FLIgtGDAvVGkCKGOJb1bR%2Fuploads%2FdRrlOjQgHtRQh8cDDPdn%2FMicrohard_flow_control3.jpg?alt=media&#x26;token=ca715170-f5f4-4480-b0de-132de67be27c" alt=""><figcaption></figcaption></figure>