The implementation of the SEG standard described in the companion paper, “Structure of the SEG Point Data Exchange and Field Formats (A Proposed SEG Digital Recording Standard)—Specification” is best done as a hierarchy of routines. Each hierarchical level progressively deals with increasingly specific data conversion operations until the whole process from pure characters to user specified parameters is complete. In this way a robust design is completed which clearly separates aspects of the standard. For example, design decisions related to character representation, control record structure, and data record conversion are carefully separated. The user can specify the data fields required, yet also retain control over storage allocated to buffers and formatting arrays. The listing of Fortran code shows the use of the SEGPD I/O routines by example utility programs. Machine dependent primitive I/O and data conversion routines are carefully specified.