NB: every browser displays these symbols a little differently.
Not all browsers will show every symbol.
I was looking for the SM ASCII code for quite a while, and couldn't find it in any answer blogs or ASCII lists.
I actually stumbled onto the SM code when I took all the possible numbers for ASCII code and threw them up on a test page.
|©||© or ©||Copyright|
|®||® or ®||Registered|
|™||™ or ™||Trademark|
|⅌||⅌||Trademark in a box|
|ⅎ||ⅎ||Trademark in a box|
|ℼ||ℼ||Trademark in a box|