RC7620-1 AT no response

Use the RC7620-1 module to send AT commands. The first few times the module will respond, but after that, the command will not respond.
Please help with this issue or what should I do.

is problem only happening after +CMUX?
have you checked +KSLEEP and see if the module has slept?

Are you seeing problem on UART or USB?

BTW, why do you need to touch AT!MAPUART?

Hi @jyijyi

Thank you for your reply.
Make sure there is no sleep. + KSLEEP: 2
Seeing problems on UART.
Set UART 1 to transmit AT command

do you see problem with USB?
do you see problem without using +CMUX?

You don’t need to use AT!MAPUART as the default setting already make the UART accept AT command

Module to be soldered to the designed PCB.We use UART only.
There will be problems without +CMUX.

how many modules are having this issue?
I don’t see problem with development kit, so wonder if this is a hardware issue on your board.