[n: To Or From Biphase Level Coding, I.e. To Or From Codes Where A One Is Coded As A Transition From A High To A Low Level During The Middle Of A Bit Cell And A Zero Is Encoded As A Transition From A Low To A High Level During The Middle Of A Bit Cell Or Vice Versa, E.g. Split Phase Code, Manchester Code Conversion To Or From Biphase Space Or Mark Coding, I.e. To Or From Codes Where There Is A Transition At The Beginning Of Every Bit Cell And A One Has No Second Transition And A Zero Has A Second Transition One Half Of A Bit Period Later Or Vice Versa, E.g. Double Frequency Code, Fm Code] {g11b 20/14a1d} Patents (Class G9B/20.039)