The Field Terminator
The field terminator character ends each field that accompanies messages. Its symbol
from puidnetd.h is PUIDNETID_MSGTERM. It's
the C language escape, "\t", is commonly used in this document, it is the ASCII
vertical tab character (VT, decimal 11)
Field Data Values
All message characters are ASCII characters. No non-printable ASCII characters
may appear. Three non-printable ASCII control characters are special. The field
terminator is one of them. The others are Carriage Return (CR, decimal 11, C
language escape "\r") and New Line (NL, decimal 13, C language escape "\n").
All other printable ASCII characters -- and only printable ASCII characters -- may appear as field data values. When any of the three proscribed characters or non-printable characters must be in data, the data must be base 64 encoded. The I2A2 external library contains C functions for base 64 encoding and decoding.