nb-iot on t-mobile in NL

[Eric Waai]

yes modem software is NB1-40343
esp32 firmware is the last stable release 1.18.1.r7

for now i waited over 1 hour without attach

[robert-hh]

@eric-waai i 1hour is too long.
what is the result of lte.send_at_command('At+CSQ') while waitung for is_attached()

[Eric Waai]

@robert-hh
AT+CSQ is usually around 23-25,99

CREG gives (1,0)
and CEREG also (1,0)

which would indicate it is somewhat connected

but CGATT gives 0

[robert-hh]

@eric-waai CEREG1,0 means:
enable network registration unsolicited result code (1) and
not registered, MT is not currently searching an operator to register to (0)
You should see something like CEREG 2,0 or CEREG 2,2 while searching.
AT+CSQ result is good. It means, the device detects a strong signal.

I'm testing with v1.20.0.rc3

[Eric Waai]

according http://m2msupport.net/m2msupport/atcreg-network-registration/
CREG 1,0
means registered, home network
on GSM
i assumed that for CEREG it meant somewhat the same
will try again tomorrow

[robert-hh]

@eric-waai As far as I understand it, the coding for CREG and CEREG is the same. The 0 means: not registered, not searching.
At my set-up, while waiting for attach, the result of AT+CEREG? is 2,2 most of the time and rarely 2,0

[Eric Waai]

@robert-hh
still not getting anywhere

this is the result of showpy

DL SYNCHRO STATISTICS

=====================
Synchro state : DRX_SLEEP
PPU SIB1 ACQ watchdog : 0
Frequency Hypothesis RF (Hz) : 0
RSRP (dBm) : -82.24
RSRQ (dB) : -12.62
Channel estimation state (Cell-spec.) : LOW CINR
Channel estimation state (UE-spec.) : LOW CINR
Channel estimation state (MBSFN) : LOW CINR
Channel estimation CINR : 5.23
Channel length : SHORT
AGC
AGC RX gain (dB) : 42.57
RX PSD BO (dBFs) : -18.79
RX PSD (dBm) : -83.06
Noise level RS (dBm) : -87.31
Digital gain (dB) : 3.90
CINR RS (dB) : 5.07
NARROWBANDS
Last DL NB : Central
Last UL NB : 0
AFC
Frequency offset RF (Hz) : -447
Frequency offset BB (Hz) : 0
PBCH
MIB received quantity : 0
MIB timeout quantity : 0

if i send AT+COPS=1,2,"20416" (tmobile specific)

i get
+CEREG: 2

+CREG: 2

OK

+CGATT: 0

OK

+CEREG: 1,2

OK

+CFUN: 1

OK

OK

OK

+CGATT: 0

OK

+CEREG: 1,2

OK

+CFUN: 1

OK

OK

as return

if i later again send AT+C(E)REG
i get +CREG: 1,0
lte.isattached() is still false

but the statistics change

DL SYNCHRO STATISTICS

=====================
Synchro state : CELL_ACQUIRED
PPU SIB1 ACQ watchdog : 0
Frequency Hypothesis RF (Hz) : 0
RSRP (dBm) : -82.88
RSRQ (dB) : -11.70
Channel estimation state (Cell-spec.) : HIGH CINR
Channel estimation state (UE-spec.) : LOW CINR
Channel estimation state (MBSFN) : LOW CINR
Channel estimation CINR : 6.45
Channel length : SHORT
AGC
AGC RX gain (dB) : 42.49
RX PSD BO (dBFs) : -20.98
RX PSD (dBm) : -84.72
Noise level RS (dBm) : -89.38
Digital gain (dB) : 5.66
CINR RS (dB) : 6.50
NARROWBANDS
Last DL NB : Central
Last UL NB : 0
AFC
Frequency offset RF (Hz) : -452
Frequency offset BB (Hz) : 0
PBCH
MIB received quantity : 0
MIB timeout quantity : 0

[robert-hh]

@eric-waai b.t.w.: which apn have you specified?
I found a link where some of that is discussed: https://forum.iot.t-mobile.nl/topic/25/nieuwe-settings-voor-nb-iot-hardware-en-api/11

[Eric Waai]

@robert-hh
hmm i can try that settings
i used this settings
Frequency Range: Guard Band
Radio band: band 8, 900 Mhz
APN: cdp.iot.t-mobile.nl
PLMN ID: 20416
NCDP address for Neul Messaging (CoAP): 172.27.131.100 Port 5683
CDP address for UDP messaging: 172.27.131.100 Port 15683
Hostname for using the API: https://iot.netwerk.t-mobile.nl
Supported TLS certifications: TLS v1.1 and TLS v 1.2

as described here
https://docs.iot.t-mobile.nl/docs/general-settings

[robert-hh]

@eric-waai These settings should be fine then.