# iwconfig ath0 txpower -1
# iwlist ath0 tx
ath0 8 available transmit-powers :
0 dBm (1 mW)
6 dBm (3 mW)
8 dBm (6 mW)
10 dBm (10 mW)
12 dBm (15 mW)
14 dBm (25 mW)
16 dBm (39 mW)
18 dBm (63 mW)
Current Tx-Power=32767 dBm (-2147483648 mW)
# iwconfig ath0
ath0 IEEE 802.11b ESSID:""
Mode:Master Channel:0 Access Point: Not-Associated
Bit Rate:0 kb/s Tx-Power=32766 dBm Sensitivity=1/1
Retry:off RTS thr:off Fragment thr:off
Encryption key:off
Power Management:off
Link Quality=0/70 Signal level=-256 dBm Noise level=-256 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
The interface is not up. Clearly, input values should be screened for out-of-bounds errors on upside and downside.
# iwconfig --version
iwconfig Wireless-Tools version 28
Compatible with Wireless Extension v11 to v20.
Kernel Currently compiled with Wireless Extension v19.
ath0 Recommend Wireless Extension v13 or later,
Currently compiled with Wireless Extension v19.
# uname -a
Linux gateway 2.6.16.62