User's Manual

The Point Six, Inc. 418 MHz wireless temperature transmitters require a compatible
receiver with the ability to receive, error check and provide RS232 and RS422/485
interface. This document describes the data format provided by the HA8-WOW, HA9-
WOW or HA10-WOW 418 MHz. Receivers.
The transmit packet from a receiver is approximately 15 milliseconds in duration and
consists of 13 bytes of data:
1-byte ID/Mode field
8-byte serial number
2-byte temperature data
2-byte CRC-16 error check
The WOW receivers process this packet. The receivers perform a CRC-16 error check
on the packet. If the data is not accurate it is discarded. When a packet is received that is
error free it is converted to a 29-character packet and transmitted out the serial port at
19,200 Baud. The data is transmitted serially in ASCII Hex format and terminated with a
CR character. This format requires two bytes for each byte of data; 14 data bytes x 2=28
plus the CR is 29 characters
The resulting binary data format of the packet is:
1-byte ID field this field will contain a byte whose LSBit indicates the service
state of the transmitter, 0=normal, 1=service mode.
8-byte serial# this field contains the serial number of the 1-Wire sensor.
2-byte temperature this field contains the temperature data stored MSB first in two's
compliment 16-bit form of 1/16 deg. C units.
2-byte CRC-16 this is the originally received data packet CRC as described above.
1-byte checksum the checksum is a mod 256 sum of all the ASCII character values
in the response but does not include the CR
Example:
D4287F44040000005A01602ED477<CR>
This field is the mode indicator, the LS-bit which indicates the
service state of the transmitter, 0=normal, 1=service mode.
D4287F44040000005A01602ED477<CR>
This field is the unique serial number of the 1-Wire temperature
sensor.