XBee Channel Setting

I am a little confused about channel setting on an XBee Pro using AT commands.
Available channels are shown as hexC to hex17, dec12 to dec23

I have seen websites where setting to, say, hexD is achieved by
“ATCH D” followed by dec13, implying that the XBee expects a
hexadecimal string so setting channel hex17 would be done by
Sending “ATCH 17” followed by dec13.
This interpretation is supported by screen shots from XCTU.

I have also seen suggestions that the XBee expects a single byte whose
binary value is the required channel. This would imply that to set channel
HexD should be done by sending “ATCH “ followed by dec13 followed by another dec13.

These interpretations are incompatible. Which of is true, please?

The 802.15.4 XBee modules use a signal hex byte for the channel. For example, the ATCH is in ASCII with ASCII values. That is to say, if I want to set the radio to channel C, then the command in ASCII characters is ATCHC
If I want to set it to channel 10, then the command would be ATCHA.

So what i am saying is that while the channels are Hex, you issue the Hex as an ASCII characters.

A B C D 14 15 16 17