[GL-X750 spitz]: testing Telit LM940/LM960 modems

phenobarbital · 2020-08-23T22:47:11.380Z

Hi!
Currently, I have some GL-X750 routers, I removed the EC25 (cat4) and set up and tested two different modems: a Telit LM940 and a Telit LM960, for some reason (I think is about power consumption), the LM940, I got faster speeds than the LM960 (AT&T: 80/30 vs 60/20), even I tried to compile a new version for X750 based on OpenWRT 19.07, the firmware run well, but the CAT11 modem is slower than CAT18.
I think is a problem with power consumption, because the Telit LM960 need 1200mA and 3.3V.
It’s possible to put more power (at least 2A) to spitz router?.
PD: and yes, Telit LM940 (a cat11 modem) works flawlessly well on Spitz, I get with Verizon speeds of 80D/50U.

robotluo · 2020-08-24T09:46:36.381Z

phenobarbital:

he CAT11 modem is slower than CAT18.

If I understand correctly, it is normal for CAT11 to have a lower rate than CAT18

phenobarbital · 2020-08-24T12:04:55.793Z

Yes, but I go lower rate from CAT18, that is exactly what is happening to me, CAT11 got higher rates and more speed than CAT18, also, CAT18 takes much longer to be available and sometimes doesn’t turn on at all, fail with an error “USB error -37”, for that reason I think is a problem related to the power consumption of CAT18.

alzhao · 2020-08-25T13:50:23.769Z

Seems like a power issue.

Spitz only has USB2.0 so I am not sure if it really works with high CAT modems.

When using EP06, I can generally get 60 to 80 Mpbs in cities. I got max 110Mbps using EP06.

Seems your CAT11 and CAT18 modems does not work in full speed in Spitz.

phenobarbital · 2020-08-25T23:24:38.422Z

Well, the CAT11 works to a good speed (80/60 and more), my concern is with CAT18, that I can’t get even the half of the speed on CAT18.
gl-inet has some routers with USB3 suppor to run high CAT modems.

alzhao · 2020-08-26T03:58:34.848Z

B1300 has USB3 but it is USB-A. You may need a PCIE->USB adapter to try.

phenobarbital · 2020-08-29T01:51:54.347Z

Well, my question over the GL-x750 is:
can I put more power over the X750 (at least 2.5A) to try to cover more powerful modems or is risky? I will be afraid if I burn my modem trying to put more power into it.
I think that if i cover at least the usual power consumption of LM940 (650mA to 700mA) maybe the modem can work without any issues, but I’m speculating.

alzhao · 2020-08-31T03:15:48.027Z

There is current limiting so you may not burn your modem by doing that.

phenobarbital · 2020-08-31T16:58:39.252Z

And, which is the limit?, 1.5A?, 2A?, 2.5A?

alzhao · 2020-09-01T10:42:03.141Z

1.5A current limit for X750

RichP · 2020-09-12T15:57:37.572Z

@phenobarbital Are you still using the LM940 in the X750? Did you need to tape some of the pins to get it to work?