It is also possible to pack frames into channels. This technique allows to transfer large frames and also manage data transfer. Channels allow to multiplex several frames and transffer them simultanously. One frame is usually transferred in multiple packets.
0123 4567 8901 234... MGID CHID FRSZ FRDT..
Table 27. Packet with Channel Support
| Item | Size | Description |
|---|---|---|
MGID | 4 | Packet idenfiticator (magic id), expected value: 0xF2 0x87 0x05 0xA3 |
CHID | 4 | Channel ID - same as frame type |
PKSZ | 4 | Packet size (number of bytes) |
PKDT | Defined in PKSZ | Packet Data, size is defined in PKSZ |
Transferred data are same as defined for frames. Items MGID, FRTP, FRSC from original frame structure are not transffered. All other items are included.
Note
This feature can be implemented step by step. Easist implementation is frame type=1.
Example of data frame transfer using channels. Frame is packed in two separate packets. Total size of transferred data is 15 bytes..
Packet 1: 0xF28705A3 (MGID) 0x00000001 (channel id) 0x0000000A (size of data in the packet) 0x0000000F (size of frame, type 1) 0x12345678 0x1234 (data - 6 bytes) Paket 2: 0xF28705A3 (MGID) 0x00000001 (channel id) 0x00000009 (size of data in the packet) 0x12345678 0x12345678 0x12 (data - 9 bytes)
