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PLS83-W Stops Responding | Telit Cinterion IoT Developer Community

August 19, 2022 - 7:35am, 874 views

We are looking to replace our PLS62-W modem with a PLS63-W or PLS83-W. During testing of the new modems, we have occasional seen the modems stop responding while on an active TCP call. When this happens, we cannot send any AT commands until the modem is restarted. We're using the same host board as our PLS62-W units, of which we have more than a thousand units running without issue.

Here's a simplified log of what we see. You'll see the modem start up and our connection get established. In this case the TCP connection is OK for 25 minutes, sending around 1 MB per minute and maintaining a moderate temperature around 42 degrees.

For no apparent reason we then see the modem assert its flow control line and stop responding. We turn off the DTR line to try and drop the data connection, but still no response. After 10 seconds we restart the modem and finally see CTS return to active and the modem start responding again.

^SYSSTART
AT&f
OK
ATI1
Cinterion
PLS83-W
REVISION 01.202
A-REVISION 01.000.04
OK
AT^SSET=1
OK
^SSIM READY
AT&S1
[DSR Off]
OK
AT+CPIN?
+CPIN: READY
OK
+CIEV: prov,1,"ROW_Generic_3GPP*"
AT^SICA=1,1
OK
AT^SISS=0,"srvType","Socket"
OK
AT^SISS=0,"conId","1"
OK
AT^SISS=0,"address","socktcp://***.***.***.***:***x;etx"
OK
[DTR On]
^SISW: 0,1
AT^SIST=0
CONNECT
[DSR On]

Online for 25 minutes. Sent 26 MB. Modem temperature 42 degrees. Modem voltage 3.8 V

[CTS Off]
[DTR Off]
[Delay 10 sec]
[Restart Modem]

[CTS On]
[Power Indicator Off]
[Power Indicator On]

^SYSSTART

This is not happening that often, but it is a concern that we'd like to address before switching modems. Do you know of any reason this could be happening, or if there is a newer version of firmware?

Thanks,

Tim