GPy with Hologram.io SIM

[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?

[tlanier]

@chrisgammell

After moving the unit to a different office, I'm now getting:

+CEREG: 2,4
+CSQ: 99,99

@jmarcelino has indicated that I have the wrong type of antenna.

[jmarcelino]

@tlanier
RSSI (from CSQ) is only one measurement. Are you still not seeing CEREG returning 2,5 ?

Ideally you'd use an antenna supporting 700Mhz bands, of course your antenna works on that frequency but doesn't appear designed for it so you may be losing some signal.

Can you increase the delay on your attach loop to 5s time.sleep(5) and add at('AT+CEER') at each iteration to see if there's any error reported?

[tlanier]

@jmarcelino

I'm available to allow you to remote into our system anytime.

I'll order a new antenna today if you want to wait until I have the correct antenna.

[tlanier]

@jmarcelino

Here's what I'm getting now after increasing the delay to 5 secs in loop with the AT+CEER command. I updated the image to show the correct time counter.

[jmarcelino]

@tlanier
Thanks. Unfortunately it's not very helpful in this situation but keep the CEER in the code if you do get a valid CSQ again it may show a reject cause.

It might be the case that the modem is connecting but being rejected by the network for some reason and then we'll know why...

[tlanier]

@jmarcelino

Hologram tech support suggested plugging the SIM into an unlocked cell phone for testing.

When we plug the SIM into an unlocked Samsung S5 phone, "TMobile-Hologram" shows up in the Available Network Operators.

When we try to go to a web page (google.com), we get an off line error page.

We were able to send a text message to the Samsung S5 from the Hologram Dashboard.

I'm not sure what this really proves since we're trying to use the SIM to attach to Verizon's CAT-M1 network.

[jmarcelino]

@tlanier said in GPy with Hologram.io SIM:

When we try to go to a web page (google.com), we get an off line error page.

Umm that should work, you should be able to load Google.com. Do you have data left?

[tlanier]

@jmarcelino

The Hologram dashboard shows I have used 104 bytes of a 1MB - Developer Plan. I assume the usage is due to the SMS message that was sent successfully.

Interesting discovery (not sure what it means):

In the Logs section of the dashboard under "Message sent from GPy"

DATA: Socket error: timed out
RAW VIEW:
{"success":true,"data":{"id":5792718,"logged":"2018-04-17 19:33:13.876522","orgid":2262,"deviceid":164756,"record_id":"2b868012-4276-11e8-a470-0242ac120002","device_metadata":"{}","data":"{"received": "2018-04-17T19:33:13.798433", "authtype": "deviceid", "tags": ["DEVICE_164756", "API_RESP"], "device_name": "GPy (30674)", "source": 164756, "messageid": "2cb19d53-4ff4-415a-b3b2-7606267d8325", "record_id": "2b868012-4276-11e8-a470-0242ac120002", "data": "U29ja2V0IGVycm9yOiB0aW1lZCBvdXQ=", "device_id": 164756}","matched_rules":[],"tags":["API_RESP","DEVICE_164756"]}}

DATA: Socket error: [Errno 111] Connection refused
RAW VIEW:
{"success":true,"data":{"id":5804366,"logged":"2018-04-18 18:41:10.684172","orgid":2262,"deviceid":164756,"record_id":"10604cb0-4338-11e8-bb29-0242ac120002","device_metadata":"{}","data":"{"received": "2018-04-18T18:41:10.361416", "authtype": "deviceid", "tags": ["DEVICE_164756", "API_RESP"], "device_name": "GPy (30674)", "source": 164756, "messageid": "b72e25a1-8c12-4235-b463-71f03544bf74", "record_id": "10604cb0-4338-11e8-bb29-0242ac120002", "data": "U29ja2V0IGVycm9yOiBbRXJybm8gMTExXSBDb25uZWN0aW9uIHJlZnVzZWQ=", "device_id": 164756}","matched_rules":[],"tags":["API_RESP","DEVICE_164756"]}}

[tlanier]

@jmarcelino

My hardware guy got the antenna vendor (San Jose Technology, Inc.) to send us a spec for the Penta Band PCB Antenna Model: EPH-502 that we are using.

The spec shows:

Frequency: 704~960; 1710~2690MHz

Antenna Spec PDF

[jmarcelino]

@tlanier
Ok that's fine then - and different from what was listed on the website.

[ChrisGammell]

@tlanier If you're seeing these messages on the dashboard it means your phone (assuming that was the phone) is able to authenticate on our network. I think it might be another red herring though, unless you want to debug why they phone isn't connecting as well.

[tlanier]

@chrisgammell

We really don't care about the phone. We were just trying to prove the SIM was functional.

The code in the GPy tried one time to run the detach function at the beginning of the program and failed. It turns out the detach function is misspelled.

Manual entry @ 6.2.26 LTE

lte.dettach()

Detach should only have one "t".

Why the lte.isattached() function returned True one time is unknown. It occurred after the laptop had gone to sleep and was reawakened.

[tlanier]

@jmarcelino

I think I've just proved that there may be a bug in the lte.send_at_cmd() command. Internally the function must time out if it does not receive an "OK" response from the modem after a period of time. Your timeout may be too short.

See the response to the "ATI" command shown below. The program error'ed out because it was expecting a different response from the AT+CEREG? command. Instead it got the trailing remains of the previous ATI command.

I believe you should clear the input buffer before sending any AT command to the modem to help prevent such a problem.

[tlanier]

@jmarcelino

I accidentally sent a message to Chris which I meant to send to you concerning the possible bug with the lte.send_at_cmd() function. I assume you will see it; I couldn't figure out how to redirect the message to a different person.