diff --git a/aircon.sh b/aircon.sh
index a0e449d..1142ea3 100755
--- a/aircon.sh
+++ b/aircon.sh
@@ -1818,10 +1818,10 @@ fi
 
 ALLARGS="$ALLARGS $*"
 
-optstring="A:bcD:f:hHi:I:k:l:Lo:pmRsSt:T:wWx:y"
+optstring="aA:bcD:f:hHi:I:k:l:Lo:pmRsSt:T:wWx:y"
 while getopts "$optstring" i $ALLARGS; do
     case "$i" in
-        A)
+        a)
             ARPING=${OPTARG}
             ;;
         b)