Yeah, it's all about diversity. One factory with six or seven different production lines to produce different variants of the same cookie-cutting radio.There are two United Kingdom resources claiming to have the "N" version, but as you can see in my previous post, the photo which MOONRAKER provided is not convincing.
I stumbled onto this.
NOISE REDUCTION The menu on the AT-5555N II only has one noise cancelling feature. NR but it is adjustable. My initial impression of the noise reduction on the AT-5555 Plus /N is that it is too aggressive. Some background artifacts almost like FM broadcasts bleed through, but we don’t have any FM transmitters nearby. Need to play with it some more, but it resembles setting 5 on the N II and tends to distort the received audio. It also takes a few milliseconds to start working which is a bit frustrating. The other thing with the noise reduction is that you have to go into the menu to activate and deactivate it. This is a pain. You need it on a button and you need it adjustable. Adjust it in the menu and activate it on a switch. The AT-5555 Plus has 8 switches with 15 functions…surely 2 of those could be repurposed? Better still: put the echo controls into memory and put the NR and NC on the echo knobs so it could be readily adjustable. NC? So far it just seems to make more noise. Not much, but certainly doesn’t reduce it on Sideband. Another thing I noticed on this radio and not on the earlier versions of the AT-5555 that when you are in the menu the channel indicator shows the menu number. That's handy because sometimes it is tricky to know exactly where you are in the menu. Of course you will need the manual to see what the menu number is associated with. Just found out that you can’t have the Noise compander and the Noise reduction on together. Turning one on will turn the other off! The noise reduction does knock out lots of background noise…sometimes almost all the hash. Still don’t know what the compander is supposed to achieve. Time might tell.