Globalstar SmartOne Series User Manual page 60

Raw message type – Multiple Packet Version (Supported in
firmware version 2.1 and later.)
The Globalstar simplex messaging protocol provides for single and multiple packet
messaging. In the event that the user application requests a user data length exceeding 9
bytes, the SmartOne (running firmware version 2.1 or later) will automatically
"packetize" the message, that is, transmit it as multiple 9 byte packets. The ground
station appliqué will reverse the process, "de-packetizing" the message back into a single
("long") message. From the user application point of view, this eliminates the 9 byte
limitation allowing the user to compose longer messages transparently. They are
presented to the user by the Globalstar back office as complete messages of a length
longer than 9 bytes. The SmartOne supports user-defined messages (Class 1 and 2) of up
to 54 bytes.
Message type 2 shall be a Raw Payload message. This message type provides for up to
53 bytes plus 6 bits of user data. This mode is provided to enable the user to directly
send a single data burst through the network. The only bits not accessible to the user are
the message type bits needed by the receiving data processor to delineate message type
associated to the TXID. User data less than the full payload will be zero padded as
necessary. Note: Total message length will be a minimum of 9 bytes in length, and a
maximum of 54 bytes in length, and the length sent to the user will always be divisible by
9. The Raw Payload message will follow the following on-air format:
Variable
Status Byte
User Data
SmartOne Manual Rev 1.5
Byte 5 = User data byte 5
Byte 6 = User data byte 6
Byte 7 = User data byte 7
Byte 8 = User data byte 8
Bits Description
8 Bit (1:0) = 2 = Raw Payload message type:
Bit (7:2) = submask data from Raw Payload user data
variable Byte 1 = User data byte 1
Byte 2 = User data byte 2
Byte 3 = User data byte 3
.
.
.
Byte 53 = User data byte 53
DOC# 9100-0268-01 p.60