4.17Over-Air Symbol Rate (AT S163) Note: engineering function only.
This command sets the
| AT S163=n<CR><LF> | |
Where: | n = 2 | 4800 symbols/sec |
| n = 3 | 9600 symbols/sec |
Default: | n = 2 | 4800 for 12.5kHz radios |
| n = 3 | for 25kHz radios |
Read | AT S163?<CR><LF> | |
Read Return: | n<CR><LF> | |
Example: | AT S163=3<CR><LF> sets 9600 symbols/sec |
4.18Preamble Period (AT S165) Note: engineering function only.
This command enables the number of preamble blocks (each block equals 6 bytes) that are transmitted before each data packet to be changed. This preamble allows for the rise time of the transmitter as well as the minimum number of blocks required by the receiver. This allows the system performance to be changed to enable the modem to be used with different transceiver equipment. The command format is as follows:
| AT S165=n<CR><LF> |
Where: | n = 1 - 10 blocks |
Default: | n = 2 |
Read | AT S165?<CR><LF> |
Read Return: | nn<CR><LF> |
Example: | AT S165=10<CR><LF> sets a preamble of 11 blocks |
Note that a symbol period depends on the RF baud rate (as set by paragraph 4.17).
For the
For the SXn50 radio at 19200 symbols per second n = 14.
Hermes Operator Note | Page 21 of 32 |