9XTend-NEMA RS-232/485, Product Manual

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9XTend ‐ NEMA™ RS ‐ 232/485 RF Modem – Product Manual v2.x4x [2007.01.04]
© 2007 MaxStream, Inc., Confidential & Proprietary ‐ All Rights Reserved 49
TX (Transmit) Request: 16-bit address
API Identifier Value: 0x01
A TX Request message will cause the modem to send RF Data as an RF Packet.
Figure 4 ‐ 7. TX Packet (16 ‐ bit address) Frames
Figure 4 ‐ 8. Example: TX Packet API Frames
TX (Transmit) Status
API Identifier Value: 0x89
When a TX Request is completed, the modem sends a TX Status message. This message will indi-
cate if the packet was transmitted successfully or if there was a failure.
Figure 4 ‐ 9. TX Status Frames
NOTE: “STATUS = 1” occurs when all retries are expired and no ACK is received.
“STATUS = 3” occurs when a packet is purged due to a ‘Polled Remote’ not receiving a poll.
RX (Receive) Packet: 16-bit address
API Identifier Value: 0x81
When the modem receives an RF packet, it is sent out the UART using this message type.
Figure 4 ‐ 10. RX Packet (16 ‐ bit address) Frames
cmdData 0x01
Length Checksum Start Delimiter Frame Data
Identifier-specific Data API Identifier
MSB LSB 0x7E 1 Byte API-specific Structure
Frame ID (Byte 5)
Identifies the UART data frame for the host to
correlate with a subsequent ACK (acknowledgement).
Setting Frame ID to ‘0' will disable response frame.
Destination Address (Bytes 6-7)
MSB first, LSB last.
Broadcast = 0xFFFF
Options (Byte 8)
0 = Standard
1 = Disable ACK
RF Data (Byte(s) 9-n)
Up to 2048 Bytes per packet
* Length [Bytes] = API Identifier + Frame ID + Destination Address + Option + RF Data
** “R” value was arbitrarily selected
Checksum
0x18
Byte 12
Destination Address
Bytes 6-7
0xFFFF
Option
0x00
Byte 8
Frame ID**
R (0x52)
Byte 5
Length*
Bytes 2-3
0x00 0x08
API Identifier
0x01
Byte 4
Start Delimiter
Byte 1
0x7E
RF Data
1 (0x31) 2 (0x32) 3 (0x33)
Bytes 9-11
cmdData 0x89
Length Checksum Start Delimiter Frame Data
Identifier-specific Data API Identifier
MSB LSB 0x7E 1 Byte API-specific Structure
Frame ID (Byte 5) Status (Byte 6)
0 = Success
1 = No ACK (Acknowledgement) received
Identifies UART data frame being reported.
Note: If Frame ID = 0 in the TX Request, no
AT Command Response will be given.
cmdData 0x81
Length Checksum Start Delimiter Frame Data
Identifier-specific Data API Identifier
MSB LSB 0x7E 1 Byte API-specific Structure
bit 0 = ACK
bit 1 = Indicate broadcast
bits 2-7 [reserved]
Up to 2048 Bytes per
packet
Received Signal Strength Indicator -
Hexadecimal equivalent of (-dBm) value.
(For example: If RX signal strength = -40
dBm, “0x28” (40 decimal) is returned)
Source Address (Bytes 5-6) RSSI (Byte 7)
MSB (most significant byte) first,
LSB (least significant) last
Options (Byte 8) RF Data (Byte(s) 9-n)