GPy with Hologram.io SIM

jmarcelino

I'm afraid the manual is written by Sequans (who make the modem) and is more of a general guide for all possible implementations.

The LED on the FiPy/GPy is only connected to the ESP32/MicroPython and not to the modem. The SQNLED command will have no effect.

The correct way to check for correctly registration is via AT commands and specifically the status check AT+CEREG? Valid registration stats are 2,1 or 2,5 (for MVNOs)

tlanier

@jmarcelino

Thanks, I've updated the code.

tlanier

@tlanier
I took the Gpy 50 miles down Interstate 85 through West Point, GA and Opelika, AL. The device never attached to a cell tower during the entire trip.

jmarcelino

@tlanier
Were you using the code you posted below? I didn't notice you had changed the code you to calling lte.attach() again. Have you been doing the other tests with this?

For setups like Hologram where you do a custom init you need to remove lte.attach() and use AT+CEREG=2 and AT+CFUN=1 manually.

As you already have those in the code you need to remove lte.attach() otherwise it will cause problems.

tlanier

@jmarcelino

Thanks for catching the misunderstanding!

Here's my revised code. The at(cmd) function has been improved to return the modem response as a list making it easier to parse. I've also added logic to break on <tac> = 1 or 5 just in case the isattached() function is not working.

I will take the GPy north towards Atlanta today and see if I can connect there.

import pycom
import socket
import ssl
import sys
import time
from network import LTE

# send AT command to modem and return response as list
def at(cmd):
    print("modem command: {}".format(cmd))
    r = lte.send_at_cmd(cmd).split('\r\n')
    r = list(filter(None, r))
    print("response={}".format(r))
    return r

#######################################################
print("CAT M1 Test - V0.3 - 4/15/18")

print("disable MicroPython control of LED")
pycom.heartbeat(False)
pycom.rgbled(0xFFFFFF)  # White

print("instantiate LTE object")
lte = LTE(carrier="verizon")
print("delay 4 secs")
time.sleep(4.0)

if lte.isattached():
    print("LTE was already attached, disconnecting...")
    lte.disconnect()
    lte.detach()
    print("resetting modem...")
    lte.reset()
    print("delay 5 secs")
    time.sleep(5.0)

# enable network registration and location information, unsolicited result code
at('AT+CEREG=2')

print("full functionality level")
at('AT+CFUN=1')
time.sleep(1.0)

# using Hologram SIM
at('AT+CGDCONT=1,"IP","hologram"')

print("attempt to attach cell modem to base station...")
# lte.attach()  # do not use attach with custom init for Hologram SIM

i = 0
while True:
    # get EPS Network Registration Status:
    # +CEREG: <stat>[,[<tac>],[<ci>],[<AcT>]]
    # <tac> values:
    # 0 - not registered
    # 1 - registered, home network
    # 2 - not registered, but searching...
    # 3 - registration denied
    # 4 - unknown (out of E-UTRAN coverage)
    # 5 - registered, roaming
    r = at('AT+CEREG?')
    r0 = r[0]  # +CREG: 2,<tac>
    r0x = r0.split(',')     # ['+CREG: 2',<tac>]
    tac = int(r0x[1])       # 0..5
    print("tac={}".format(tac))

    if lte.isattached():
        print("Modem attached (isattached() function worked)!!!")
        break

    if (tac==1) or (tac==5):
        print("Modem attached!!!")
        break

    i = i + 1
    print("not attached: {} secs".format(i))

    if (i % 2 == 0):
        pycom.rgbled(0xFF0000)  # Red
    else:
        pycom.rgbled(0x000000)  # Off

    time.sleep(1)

print("connect: start a data session and obtain an IP address")
lte.connect()
i = 0
while not lte.isconnected():
    i = i + 1
    print("not connected: {}".format(i))

    if (i % 2 == 0):
        pycom.rgbled(0x00FF00)  # Green
    else:
        pycom.rgbled(0x000000)  # Off

    time.sleep(1.0)


pycom.rgbled(0x0000FF)  # Blue

s = socket.socket()
s = ssl.wrap_socket(s)
s.connect(socket.getaddrinfo('www.google.com', 443)[0][-1])
s.send(b"GET / HTTP/1.0\r\n\r\n")
print(s.recv(4096))
s.close()

lte.disconnect()
lte.dettach()

# end of test, Red LED
print("end of test")
pycom.rgbled(0xFFFF00)  # Yellow

while True:
    pass

tlanier

@tlanier

I drove through both Newnan, GA and Peachtree City, GA with the GPy running in my car. The device never attached to any tower even though I passed by many towers within visible sight.

jmarcelino

Thanks @tlanier

Are you able to try it with a Verizon Cat M1 SIM?

tlanier

@jmarcelino

Anybody know how to get an evaluation Cat M1 SIM that will work.

On the Verizon web page they state: "Machine to Machine Plans are available only to business customers with five or more CLEU lines that have signed a Major Account Agreement. "

Verizon Machine to Machine Plans

I talked to Kore about a month ago, and they did not offer Cat M1 SIM's at that time.

Kore

tlanier

@tlanier

We've talked to the Verizon open development team and they indicated that CAT M1 is on ALL Verizon LTE towers in the country.

There's got to be some explanation as to why we cannot connect with the GPy.

tlanier

@tlanier

The Verizon Wireless HelpDesk @ 800-525-0481 has now told us our Hologram SIM is not a valid SIM on their network. We have contacted Hologram to try to determine what could be the problem. No word yet from Hologram.

ChrisGammell

@tlanier said in GPy with Hologram.io SIM:

The Verizon Wireless HelpDesk @ 800-525-0481 has now told us our Hologram SIM is not a valid SIM on their network

Yep, still trying things here as well. As Ryan said over on our forum, it's possible that Verizon does not have direct records of our SIMs on their network and we encourage everyone to contact us directly for connectivity. We understand you're frustrated while we try to get this sussed out, we are as well. The problem with SIM cards that normally "just work"...is when they don't.

ChrisGammell

@chrisgammell

Speaking of frustrated, I'm still getting errors from lte.connect(), is there a way to get a more verbose output?

I just saw in the docs that there is a firmware update for the modem as well as as the Pycom boards themselves, going to try that now. Is it possible that that could be contributing to the problem?

ChrisGammell

I added at('at+csq') into the loop and saw that as the device eventually finds its way onto the network here locally, it goes from "99, 99" to "11, 99" or so. Does yours change if you insert that into the loop, @tlanier? Also could you post a picture of your mobile rig? I'm curious about how you have it all hooked up and powered and such.

tlanier

@chrisgammell

I did do the firmware update from:

https://pycom.io/downloads/

I have not done the modem firmware update. Thanks for the link. I will try that first thing in the morning.

tlanier

@chrisgammell

I'm just using the expansion board 2.0 with the GPy powered using the USB port to my computer desktop. I've also drove around in the car with the unit plugged into the USB port on my car.

I'll try the AT+CSQ command in the morning and post the results.

As a new user the system will only allow me to post every 10 mins so I sitting here waiting for the 10 mins to expire so I can send this post...

jmarcelino

Thank you both so much for your continued tests.

@ChrisGammell We're investigating your .connect() problems. I think our command timeouts were very short for some situations and I've let the LTE team know, hope to see an improvement on the next release.

Modem firmware could have an impact but it's hard for us to tell because our modem manufacturer, very much like Verizon, just doesn't understand roaming MVNOs like Hologram. They only think in terms of carrier certification with the carrier's own SIM card.

That said it won't harm anything to try a newer modem firmware as long as you are careful with the upgrade - give it lots of time to complete even when it seems nothing is happening!

We should be releasing a more streamlined modem upgrade process soon so you can also wait for that instead.

If anyone else can help us run some tests with Hologram especially in a known good coverage area where you already see 2,5 and valid CSQ let us know. It would help if perhaps someone can give us remote access (e.g. TeamViewer) to check out a few parameters.

tlanier

@chrisgammell
I'm getting a +CSQ: 11,99 here indoors.

tlanier

@chrisgammell

Nothing special about the setup.

jmarcelino

@tlanier
Which antenna is that? Do you have a link?
Is it suitable for 746-787Mhz (Band 13) operation?

tlanier

@jmarcelino

I've moved the unit to a front office where I'm now getting +CSQ: 15,99 signal strength.

You may have discovered my problem about the antenna.

My hardware guy is not here at this moment, but this is the part number I got off our last order which is what we use for our 4G LTE modems connecting to T-Mobile.

Antenna Specs

Would the fact that I'm now getting a signal strength of 15 not indicate that the antenna is sufficient?

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