Returns TRUE if user record number record is registered in conference conf

---

See also: U_Bdl, U_BdlDay, U_Bul, U_Fdl, U_Ful, U_LDate, U_LDir, U_Lmr, U_Logons, U_LTime, U_MsgRd, U_MsgWr, U_Name, U_PwdHist, U_PwdLc, U_PwdTc, U_RecNum, U_Stat, U_TimeOn