The rules that use the category "<controller>" are:

<air_command_prefix-roger>

<controller> <roger>

<roger> <controller>

<roger> <unit_call_sign> <controller>

<unit_call_sign> <controller> <roger>

<unit_call_sign> <roger> <controller>

<air_command_prefix>

<controller>

<controller> <roger>

<roger> <controller>

<roger> <unit_call_sign> <controller>

<unit_call_sign> <controller>

<unit_call_sign> <controller> <roger>

<unit_call_sign> <roger> <controller>

<communications_directive>

<radio_contact_verb> <controller>

<radio_contact_verb> <controller> on <frequency_code>

<radio_contact_verb> <controller> on <frequency_code> prior to <point_name>