when you say the inscription of the ring is written in the same mode as the "nine" that has a secret spot on every LotR-characters body, it's not completely true. there are several modes to use the same signs, and the mode on the ring is like the Grey Elves (the Sindar) would write: Sindarin. the nine is written in the Quenya way (Noldor). the only big difference - apart from some changing sounds and secondary sounds - is that in Quenya you first write the tengwa (p, t, k, l) and then put the Tehta above, so it is read in an upward motion(each group of signs can be read as pe, te, ke, le). sindarin is the other way around: first the Tehta, and then you draw the tengwa beneath it (each group of signs can be read as ep, et, ek, el).
those who are interested in learning these characters, just go to
http://www.sci.fi/~alboin/tengwartutorial.htm. the font can be found on
http://www.acondia.com/tengwar_fonts/