So far ,I found two way to boot ws100 fxs from TTL port
before ws100 is reseted.change RxD on TTL side with Ground.when you get a stable Dark Green window.change the Rxd back.So you can input any command.
2.Normal boot mode.
You can change boot parameter by command ‘c’.
soft reset by ‘g 10000′.
however,I can not find any command like NIOP ,PFLASH end etc. to update firmware.’c’ command does not work with TFTP even though I had tried every combination.so far I can not boot my box by staying on LED 3.
I really appreciated if there is any one who can tell me how to enter NIOP mode!