Welch Allyn TM 262 Auto Tymp - User Manual - Manual (Page 70)

TM 262
5-4 Revised 4/11/08
Record Formats
General record format
All output records are transmitted in a predefined, fixed length format. The generic format for
all records is:
Each record contains only printable ASCII characters, other than the terminating “CR” “LF”
characters. Each record consists of fixed length data fields with any unused data fields filled
with a value of 0. The Record Sequence Number is a value from 0 to 9, which is incremented
by 1 for each new record transmitted. This value will wrap around from 9 to 0. A record will be
retransmitted with the same sequence number if retransmission is necessary due to a
communications error.
The Record Index Number is a value from 0 to 8 which indicates the record number within a
group of records when all test results are transmitted. For example this value will identity a
record as Record 1 of 5 or Record 7 of 8 when used in conjunction with the Total Record
Number. If only the currently displayed record is being transferred, this value will be 1.
The Total Record Number is a value from 1 to 8 which indicates the total number of records to
be transmitted in a group when all tests results are transmitted.
The Checksum is calculated as the mod 256 sum of all preceding characters in the record,
including the “:” prefix, with the most significant bit = 0 and stored as two Hex ASCII
characters.
“.” Record
Type Record
Sequence
Number Record
Index
Number Total
Record
Number Data
Fields Checksum “CR” “LF”