Codan Radio P25 Training Guide - Manual (Page 69)

P25 RADIO SYSTEMS | TRAINING GUIDE
Chapter 4: Anatomy of the Common Air Interface Page 61
Manufacturer’s ID (MFID)
The MFID standard value of $00 is used unless the data packet contains a nonstandard (manufacturer
specifi c) control channel message. $01 is reserved.
Logical Link ID
The Logical Link ID is the location that the data packet is being sent to, or received from (Source or
Destination ID of the subscriber).
Full Message Flag (FMF)
%0 All subsequent retries
%1 First try for complete packet (Unconfi rmed Data Packet always uses 1)
Blocks to Follow
Blocks to Follow indicates the number of blocks in the Data Packet, not including the header.
Pad Octet Count
The Pad Octet Count is the number of pad octets that have been added to the User data to form a
complete block.
Syn
Syn is a fl ag used to re-synchronize the sequence numbers of the packet when asserted, for specially
defi ned registration messages. Syn is used for Confi rmed Data Packets only.
N(S)
N(S) is the sequence number of the packet used to identify each request packet so that the receiver
may correctly order the received message segments and eliminate duplicate copies. N(S) is used for
Confi rmed Data Packets only.
FSNF
The Fragment Sequence Number Field is used to consecutively number message fragments that make
up a longer data message. FSNF is used for Confi rmed Data Packets only.
Data Header Offset
The Data Header Offset is used to divide the Data Block into a data header and data information. A
Data Header Offset is only used in some applications.