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

<full_unit_call_sign>

<unit_call_sign>

<contact_command_mod>

<assign_prefix> <unit_call_sign>

<air_command_prefix-roger>

<roger> <unit_call_sign>

<roger> <unit_call_sign> <controller>

<unit_call_sign> <controller> <roger>

<unit_call_sign> <roger>

<unit_call_sign> <roger> <controller>

<air_command_prefix>

<roger> <unit_call_sign>

<roger> <unit_call_sign> <controller>

<unit_call_sign>

<unit_call_sign> <controller>

<unit_call_sign> <controller> <roger>

<unit_call_sign> <roger>

<unit_call_sign> <roger> <controller>