diff --git a/src/sw_sup/clocking.md b/src/sw_sup/clocking.md
index bc0cdc0..069d729 100644
--- a/src/sw_sup/clocking.md
+++ b/src/sw_sup/clocking.md
@@ -3,7 +3,8 @@
 This page describes ways to set up clocking. Official documentation references:
 
 * [Carrier configuration](https://m-labs.hk/artiq/manual/installing.html#miscellaneous-configuration-of-the-core-device)
-* Devices' [available options](https://m-labs.hk/artiq/manual/core_drivers_reference.html), [Urukul example](https://m-labs.hk/artiq/manual/core_drivers_reference.html#artiq.coredevice.urukul.CPLD)
+*
+Devices' [available options](https://m-labs.hk/artiq/manual/core_drivers_reference.html), [Urukul example](https://m-labs.hk/artiq/manual/core_drivers_reference.html#artiq.coredevice.urukul.CPLD)
 
 In general, any RF card and Carriers require some clock source. Most of them have both internal clock signal generator
 and external MMCX and/or SMA connectors to accept the signal. By default the internal clock is used for Carriers,
@@ -51,9 +52,11 @@ default-ish [CONFIG.TXT](../extra/CONFIG.TXT) to the SD card near (same level) `
 
 ## RF Devices (Except Clocker)
 
-If you want to set the clock source specifically for RF devices, you will just need to update the JSON file and [regenerate device_db.py file](device_db.md).
+If you want to set the clock source specifically for RF devices, you will just need to update the JSON file
+and [regenerate device_db.py file](device_db.md).
 
-For example for Urukul, you will just need to check the manual for available variants and apply them in the JSON file, so Urukul entry may look like this:
+For example for Urukul, you will just need to check the manual for available variants and apply them in the JSON file,
+so Urukul entry may look like this:
 
 ```json
 {
@@ -62,7 +65,17 @@ For example for Urukul, you will just need to check the manual for available var
 ```
 
 So basically, `clk_sel` and `refclk` fields need to be set:
+
 * `clk_sel` selects the source clock, where 0 - internal 100MHz XO; 1 - front-panel SMA; 2 internal MMCX
 * `refclk` - reference clock frequency in Hz
 
-These settings may need to be checked with official manual and may differ from device to device.
\ No newline at end of file
+These settings may need to be checked with official manual and may differ from device to device.
+
+## Clocker card
+
+Main page: [clocker.md](../hw/clocker.md)
+
+Clocker card allows to distribute clock signal up to 1 GHz without additional software setup. Therefore, there is no way
+to set it to generate signal, which would be different from input. The only setup allowed is to set to accept signal
+from `EXT`/`INT` ports, front-panel SMA or card's MMCX ports respectively, by switching the `CLK SEL` switch on the
+card ![](../img/clocker_ref.jpg).
\ No newline at end of file