GSOF messages: General Serial Output Format
Report packet 40h structure (GENOUT)
|
Byte |
Item |
Type |
Value |
Meaning |
|---|---|---|---|---|
|
0 |
STX |
Char |
02h |
Start transmission |
|
1 |
STATUS |
Char |
Receiver status code |
|
|
2 |
PACKET TYPE |
Char |
40h |
Report Packet 40h (GENOUT) |
|
3 |
LENGTH |
Char |
00h–FAh |
Data byte count |
|
4 |
TRANSMISSION NUMBER |
Char |
Unique number assigned to a group of record packet pages. Prevents page mismatches when multiple sets of record packets exist in output stream. |
|
|
5 |
PAGE INDEX |
Char |
00h–FFh |
Index of current packet page. |
|
6 |
MAX PAGE INDEX |
Char |
00h–FFh |
Maximum index of last packet in one group of records. |
|
One or more GSOF messages |
||||
|
Output record type |
Char |
01h |
For example, Time (Type 1 Record) |
|
|
Record length |
Char |
0Ah |
Bytes in record |
|
|
Various fields depending on Output record type. There can be various records in one GENOUT packet. There could be multiple GENOUT packets per epoch. Records may be split over two consecutive packets. |
||||
|
Length + 4 |
CHECKSUM |
– |
– |
(Status + type + length + data bytes) modulo 256 |
|
Length + 5 |
ETX |
03h |
End transmission |
|
Each message begins with a 4-byte header, followed by the bytes of data in each packet. The packet ends with a 2-byte trailer. Byte 3 is set to 0 (00h) when the packet contains no data. Most data is transmitted between the receiver and remote device in binary format.
Receiver Status code
|
Byte number |
Description |
|---|---|
|
Bit 0 |
Reserved |
|
Bit 1 |
If set, low battery at the base station |
|
Bit 2 |
Reserved |
|
Bit 3 |
If set, receiver's kinematic state is currently set to 'Roving', otherwise 'static' |
|
Bit 4 to 7 |
Reserved |