I tried to change the baudrate of RC7611 modem using AT+IPR=921600 command. Even though I get ‘OK’ response the device doesn’t switch to the desired baudrate. Here are the steps which I have followed,
arm_busybox:~# stty -F /dev/ttyO1 115200 → host device switching to 115200 baudrate
arm_busybox:~# stty -F /dev/ttyO1 -a
speed 115200 baud;stty: /dev/ttyO1
line = 0;
intr = ^C; quit = ^; erase = ^?; kill = ^U; eof = ^D; eol = ; eol2 = ; swtch = ; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase = ^W;
lnext = ^V; flush = ^O; min = 0; time = 2;
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-ignbrk -brkint ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl -ixon -ixoff -iuclc -ixany -imaxbel -iutf8
-opost -olcuc -ocrnl -onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
-isig -icanon iexten -echo -echoe echok -echonl -noflsh -tostop -echoprt echoctl echoke
arm_busybox:~#
arm_busybox:~# chat -e -t 2 -v ‘’ ‘ATI’ ‘OK’ ‘’ > /dev/ttyO1 < /dev/ttyO1
ATI
Manufacturer: Sierra Wireless, Incorporated
Model: RC7611-1
Revision: SWI9X07H_00.03.03.00 2bb7a4 jenkins 2020/04/15 07:57:29
IMEI: 353781580199220
IMEI SV: 14
FSN: 6N1494328404B0
+GCAP: +CGSM
OK
arm_busybox:~# chat -e -t 2 -v ‘’ ‘AT+IPR?’ ‘OK’ ‘’ > /dev/ttyO1 < /dev/ttyO1 → Query current modem baudrate
AT+IPR?
+IPR: 115200
OK
arm_busybox:~# chat -e -t 2 -v ‘’ ‘AT+IPR=921600’ ‘OK’ ‘’ > /dev/ttyO1 < /dev/ttyO1 → Command to switch modem baudrate to 921600
AT+IPR=921600
OK → Modem accepted the new baudrate
arm_busybox:~# chat -e -t 2 -v ‘’ ‘AT+IPR?’ ‘OK’ ‘’ > /dev/ttyO1 < /dev/ttyO1 → This command should get succeded as the modem should have switched the baudrate already. Some modems need a soft reboot to change the config so we save the current config and do a soft reboot.
AT+IPR?
+IPR: 921600
OK
arm_busybox:~#
arm_busybox:~# chat -e -t 2 -v ‘’ ‘AT&W’ ‘OK’ ‘’ > /dev/ttyO1 < /dev/ttyO1 → Save current config to NVM
AT&W
OK
arm_busybox:~# chat -e -t 2 -v ‘’ ‘AT+CFUN=1,1’ ‘OK’ ‘’ > /dev/ttyO1 < /dev/ttyO1 → Soft reboot
OK
arm_busybox:~# stty -F /dev/ttyO1 921600 → Switching host baudrate to 921600
arm_busybox:~#
arm_busybox:~#
arm_busybox:~#
arm_busybox:~#
arm_busybox:~# chat -e -t 2 -v ‘’ ‘AT+IPR?’ ‘OK’ ‘’ > /dev/ttyO1 < /dev/ttyO1 → NO RESPONSE
arm_busybox:~#
arm_busybox:~#
arm_busybox:~# chat -e -t 2 -v ‘’ ‘AT+IPR?’ ‘OK’ ‘’ > /dev/ttyO1 < /dev/ttyO1 → NO RESPONSE
arm_busybox:~# chat -e -t 2 -v ‘’ ‘AT+IPR?’ ‘OK’ ‘’ > /dev/ttyO1 < /dev/ttyO1 → NO RESPONSE
arm_busybox:~#
arm_busybox:~# chat -e -t 2 -v ‘’ ‘AT+IPR?’ ‘OK’ ‘’ > /dev/ttyO1 < /dev/ttyO1 → NO RESPONSE
arm_busybox:~# chat -e -t 2 -v ‘’ ‘AT+IPR?’ ‘OK’ ‘’ > /dev/ttyO1 < /dev/ttyO1 → NO RESPONSE
arm_busybox:~#
arm_busybox:~# stty -F /dev/ttyO1 115200 → switching to default baudrate(115200)
arm_busybox:~#
arm_busybox:~# chat -e -t 2 -v ‘’ ‘AT+IPR?’ ‘OK’ ‘’ > /dev/ttyO1 < /dev/ttyO1 → Modem reponse to default baudrate
+IPR: 921600
OK
