Add the following code at the start of the batchfile (or after @echo off)
ping 123.45.67.89 -n 1 -w 10000 > nul
You can ping an address that surely doesn't exist and specify the desired timeout:
ping 123.45.67.89 -n 1 -w 10000 > nul
And since the address does not exists, it'll wait 10,000 ms...