ashtech GG Surveyor Reference Manual page 193

Table 6.89 outlines the example ZDA response message.
Command/Response Formats
Table 6.89: Typical ZDA Response Message
Item
$GPZDA Message header
123123.00 UTC time
10 Current day
03 Current month
1996 Current year
+07 Local zone
*22 Checksum in hexadecimal
Description
175