I'm reading the Icom IC-51E PLUS2 manual and it says it supports the following modes:

• AM
• FM
• FM-N
• DV

What is FM-N? I'm new to amateur radio and never heard of it it before. It's not listed on the Wikipedia either: https://en.wikipedia.org/wiki/List_of_amateur_radio_modes

I'm reading the Icom IC-51E PLUS2 manual and it says it supports the following modes:

• AM
• FM
• FM-N
• DV

What is FM-N? I'm new to amateur radio and never heard of it before. It's not listed on Wikipedia either.