The FHS segment is used to head a file (group of batches) as defined in Section 2.15.3, "HL7 batch protocol."

HL7 Attribute Table - FHS - File Header

12
C.LenElement
1..1-STR1-00067FHS-1File Field Separator
2..4-STR1-00068FHS-2File Encoding Characters
3..15-STO1-00069FHS-3File Sending Application
4..20-STO1-00070FHS-4File Sending Facility
5..15-STO1-00071FHS-5File Receiving Application
6..20-STO1-00072FHS-6File Receiving Facility
7..26-TSO1-00073FHS-7File Creation Date/Time
8..40-STO1-00074FHS-8File Security
9..20-STO1-00075FHS-9File Name/ID
10..80-STO1-00076FHS-10File Header Comment
11..20-STO1-00077FHS-11File Control ID
12..20-STO1-00078FHS-12Reference File Control ID