Why is the modem returning duplicate responses to a query?

Question

linux

Hello, tell me, please, why does the modem return several identical answers for 1 request?

[email protected]:~# echo -en "AT\r\n" > /dev/ttyUSB2
[email protected]:~# AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

AT


OK

And how to pass multiple parameters in a request?
For example, CMD=AT+QICSGP=1," www.kyivstar.net "
System: Linux version 3.18.16 ([email protected]) (gcc version 4.8.3 (OpenWrt /Linaro GCC 4.8-2014.04 r46020)
Modem: Quectel uc20 Board
: HILINK HLK-RM04

Answer 1

Turn off echo.