# XBee 3 LTE-M/NB-IoT: Reading module AP setting causes outbound TCP conenction to open
**URL:** https://forums.digi.com/t/xbee-3-lte-m-nb-iot-reading-module-ap-setting-causes-outbound-tcp-conenction-to-open/38468
**Category:** XBee - Cellular
**Created:** [May 21, 2026, 3:08pm UTC](https://forums.digi.com/t/xbee-3-lte-m-nb-iot-reading-module-ap-setting-causes-outbound-tcp-conenction-to-open/38468 "2026-05-21T15:08:46Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@jackson](https://forums.digi.com/u/jackson)
#### Post date: [May 21, 2026, 3:08pm UTC](https://forums.digi.com/t/xbee-3-lte-m-nb-iot-reading-module-ap-setting-causes-outbound-tcp-conenction-to-open/38468/1 "2026-05-21T15:08:47Z")
XBee 3 LTE-M/NB-IoT cellular module.
Using XBee Studio and the Xbee TH Dev Kit.
DL=98.122.42.xxx Dest IP
OD=0.0.0.0 Operating dest IP
DE=50 Dest port
C0=51 Listen port
AP=0 Transparent mode
PS=0 Micropython disabled
I can Refresh the SETTINGS screen (cirular arrow icon) to read various module settings. No problem.
However, when I read/refresh the **AP** (API Enable) setting, a connection automatically opens to my DL, and OD becomes OD=98.122.42.xxx. Note that I am not Writing the setting, only Reading it.
Since there is an open connetion, LISTEN MODE is no longer active.
I have to ATNR to close that connection.
May have to rely on SMS to accomplish that. Ugh
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### Author:  [@mvut](https://forums.digi.com/u/mvut)
#### Post date: [May 21, 2026, 6:21pm UTC](https://forums.digi.com/t/xbee-3-lte-m-nb-iot-reading-module-ap-setting-causes-outbound-tcp-conenction-to-open/38468/2 "2026-05-21T18:21:50Z")
Any time you go to read a radios setting, you are entering command mode. If you happen to be submitting data while in command mode and issuing an AT command, it is possible that you write a new value to that AT command.
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### Author:  [@jackson](https://forums.digi.com/u/jackson)
#### Post date: [May 21, 2026, 6:35pm UTC](https://forums.digi.com/t/xbee-3-lte-m-nb-iot-reading-module-ap-setting-causes-outbound-tcp-conenction-to-open/38468/3 "2026-05-21T18:35:16Z")
That must be it. An “AT” did get sent over cellular to my TCP Server monitor. I think it was from the ATCN.
Thanks
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### Author:  [@jackson](https://forums.digi.com/u/jackson)
#### Post date: [May 21, 2026, 7:29pm UTC](https://forums.digi.com/t/xbee-3-lte-m-nb-iot-reading-module-ap-setting-causes-outbound-tcp-conenction-to-open/38468/4 "2026-05-21T19:29:29Z")
Maybe found a problem…
When reading a setting this typically occurs:
_**+++OK
ATRO
3
ATCN
OK**_
When reading AP this happens:
_**+++OK
ATAP
0
ATCN
OK
AT**_
Notice the extra “AT” at the end. That is what is being transmitted and opening the connection.
Reading the other settings doesn’t do that.
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### Author:  [@mvut](https://forums.digi.com/u/mvut)
#### Post date: [May 22, 2026, 12:13pm UTC](https://forums.digi.com/t/xbee-3-lte-m-nb-iot-reading-module-ap-setting-causes-outbound-tcp-conenction-to-open/38468/5 "2026-05-22T12:13:57Z")
That looks like it is you are sending an additional AT to the radio in your code.
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### Author:  [@jackson](https://forums.digi.com/u/jackson)
#### Post date: [May 22, 2026, 12:54pm UTC](https://forums.digi.com/t/xbee-3-lte-m-nb-iot-reading-module-ap-setting-causes-outbound-tcp-conenction-to-open/38468/6 "2026-05-22T12:54:47Z")
XBee Studio 1.3.1
XBee 3 Global LTE-M/NB-IoT FW 11621
Nope, I’m only clicking the circular-arrow REFRESH (read) buttons.
No code running.
You can see whats happening in the XBee Console window.
Only the AP setting sends the extra “AT” (I’ve not checked every other setting)
Normal Refresh of AI:
+++OK
ATAI
0
ATCN
OK
AP Refresh with the extra “AT” after ending Command Mode:
+++OK
ATAP
0
ATCN
OK
AT
If I manually type in ATAP and then ATCN, there is no extra AT.
Looks likes a Studio issue.
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### Author:  [@mvut](https://forums.digi.com/u/mvut)
#### Post date: [May 22, 2026, 1:10pm UTC](https://forums.digi.com/t/xbee-3-lte-m-nb-iot-reading-module-ap-setting-causes-outbound-tcp-conenction-to-open/38468/7 "2026-05-22T13:10:24Z")
Please use the Report Feedback option in the XBee Studio to report the issue to the Digi Engineering team.