批處理ping通就繼續不通就報警為什么出錯

echo off
:a
for /f tokens=3 delims== %%i in ('ping 123.456.789.000 -n 2^|find TTL') do (set TTL=%%i)
setlocal enabledelayedexpansion
set a=%ttl:~0,2%
echo %a%
if /i %a% leq 120 goto a else goto b
:b
ping /n 3 127.0.0.1>nul
echo  輸出報警聲
ping /n 3 127.0.0.1>nul
echo 
ping /n 3 127.0.0.1>nul
echo 
ping /n 5 127.0.0.1>nul
pause
nclick="copycode($('code0'));">復制代碼

以下連接寬帶時候結果F:bat>echo off3637363837-------------------------------以下是突然斷開連接或者網絡自己斷開的輸出結果 當然也沒有報警聲F:bat>echo off373737383736373837373637363637373737373737373737------------為什么為什么