Don't laugh okay! But what's a TD/ IS?
Can you give a little bit of context? I'm afraid it will be hard to decipher the acronyms without knowing where and how they were used.
Like when you see people post things, and you see their picture, and under that it says contributor, like literally under that. That's the only way I can describe it, for example: I am a AD/ DL. But on some other people's it says TD or IS