Router 4g Sim Card

[Leoma Cianchetti]

HelloTwice I had a defect Sim Card in the last 3 Weeks with my D-Link DWR-921 Router.

Because of traveling I stored the first Sim Card in a plastic bag for use with my mobile Router.

Home again I restored the Sim Card in my DWR-921 without connection to the Internet.

I recognized some sticky dirt on the Sim Card and removed it. The same on the card connector.

After it, I got Internet connection, but a few days later suddenly the connection drops.

The Router toggled between connection and disconnect, regardless what I tried. I restored the OEM Firmware (openwrt-19.07.6-ramips-mt7620-dlink_dwr-921-c3-squashfs-sysupgrade I used before), the same behavior. Even another Router and Smartphone wasn't working with this Sim. Calling the Helpline from that Sim card, a automatically answer says; there is a a problem with my Sim Card.

Calling the Helpline from another line, all the hints doesn't help and finally renewed the Sim Card.

The Problem was solved, for the moment.

But 2 Weeks later, the same behavior came up, the router app shows connection toggling (still OEM SW).

My question; Has anyone seen the same behavior, or explanation for this? For me it seems the Router write some wrong data to the Sim card. And is there a solution? I'm unhappy to dispose the DWR-921, I would like to flash openwrt 21.xx.

Hello trendy

Voltage supply is 12 Volt - correct value, at the Sim Card I get 1.8 Volt on one Pin, I don't know the number, because I can only measure on the board, bacause of Sim card connector housing

My intention to discuss here was the hope to find someone who has made the same experience or has deeper knowlege into the handshaking between sim card and router.

Wether I have to open the sim connector case for cleaning und take the risk to kill a third sim card or dispose the router.

Thank you all for your hints, in the next days I'll remove the housing (soldered) clean all 6 connections and make another attempt.

Strange, that no other made the same experience, I searched the net for it.

Thanks for your attention.

Worth mentioning here that this is not a good way to store a SIM card. Although they are pretty robust, SIM cards can still suffer damage from ESD, and plastic bags are potential sources of static build-up. If your card was damaged, it could explain the first failure you saw. It is even possible (although not terribly likely) that ESD damage to a SIM card could cascade to cause issues with the device using that card (i.e. the DWR-921), which could then cause damage to future cards... kind of like the famous 'click of death' that happened with Zip drives back in the day.

I've used Compex mini PCIe cards with great success. They're all Qualcomm Atheros based and they just work in Openwrt. These are proper AP wifi cards, designed for access points, not cards designed for client wifi.

If you are in OpenWrt and have access to the LuCI interface, then one of your best friends will be the System->Software page. Navigate there and click "update lists". You should see all the packages available for OpenWrt. Now just type "7915" in the filter. You should see the driver and (depending on your version of OpenWrt) perhaps its firmware. In your case, installing the driver should automatically install the firmware.

I live in the country and don't have many internet options. My prior router took a sim card, so I need a new router that does the same. However, I am not familiar enough with routers to be able to determine which uses a sim card as opposed to ethernet. It needs to be a high speed with a wide range to reach throughout a two story house with many devices connected. If I purchase a Netgear Nighthawk R7800, will I need to purchase a modem or does it have a sim slot? If I do need to purchase a modem, am I able to use my SIM card in a Netgear modem? Any help appreciated.

You may have misinterpreted my speed test. The microSD card is capable of much higher speeds than the router is capable of. It is capable of 60+ Mbps transfers on my PC, but only 13-15Mbps Read/5-6Mbps Write transfers from/to the router. Personally, I like the Kingston Canvas SD cards, but Lexar and Sandisk are also good, as long as you choose those with higher speed ratings. In particular, check the Write speeds because many SD cards have fast Read speeds, but much lower Write speeds.

My intention of the microSD card in the router is only to store/stream movies and to access miscellaneous files for travelling. Also, I can do backups of photos (jpeg, raw) wirelessly. The relatively slow speeds are adequate for my purpose, but definitely the router cannot act as a general purpose NAS storage device.

I am working at a client site today. This specific client has decided to replace their legacy 2600 branch office routers with newer 1921 ISR G2 routers as they move from a Legacy Frame WAN to a MPLS network with a different provider.

The backup in the former scenario was actually an ISDN solution. Moving forward, the provider has sold them a 3G backup solution. To support this, we have purchased Cisco line cards for the 3G. The part number for the cards is "EHWIC-3G-EVDO-V=".

I was asked by the client this morning if there was a way to tell what the IMEI number for the 3G card was. I performed a sho inventory, as well as a sho hardware, but I do not see this IMEI number. I also checked the label on the packaging box that the cards came in, but do not see this number.

I am not sure how to tell the router "cellular 0". Also when I do a "sho interface" on the router, it does not show a cellular interface (shows serial, loopback, and both ethernets, as well as an embedded service engine, but no cellular.

With potential for home automation with remote control (I don't know anything about it at the moment, I imagine that opening ports and VPN are sufficient conditions, but feel free to disabuse me of this)

Smartphone USB tethering This article relies on the following: * Accessing OpenWrt WebUI * Accessing OpenWrt CLI Introduction USB tethering is used to connect your OpenWrt Router to the Internet by using the your smartphone. It's more...

I originally used a Huwaei B818-263 in bridge mode and even though that cannot run OpenWrt that was fantastic and I'd highly recommend it but it may be a little too expensive for you. Now I use the NR7101 which can run OpenWrt but that's even more expensive.

I assume that for the "incoming connections" requirement, you can get a public IP address directly on the modem. Note: last time I have seen this outside of a "business" subscription (which is not available to a private person) was in 2011. Or you will have to use IPv6, or something like PureVPN (for the external IP, not for privacy).

Without the 5G, I would recommend a cheap Huawei E3372s stick and any OpenWRT compatible router with a USB port. Note that there is also Huawei E3372h model on sale (and it's more popular) - but it fails the "incoming connections" requirement, because it is a NAT router. Fortunately, it can be reflashed to the stick firmware.

A bit pricey indeed. Especially all the 5G routers I saw mean a huge price bump. I guess they're gonna be cheaper in a couple of years. It makes me consider seriously taking a 2nd-hand, cheap 4G router and enjoy it as long as I'm happy with the 4G bandwidth.

If by "public IP address" you mean a static one, then no, I definitely won't have it. Hence the DynDNS requirement in my list (there may be other solutions, but as far as my limited networking knowledge goes, that's the only solution that comes to mind).

Thanks for these advices. So, pardon my noobish question, but does it mean that my requirement "guest network with limited bandwidth so that they don't suck up my data plan, and also, maybe with some ports blocked (like opening only HTTPS, HTTP, IMAP and SMTP ports)" can be met with any OpenWRT-compatible router? If not, what do I have to look for in a spec sheet such as the one regarding the device I can easily buy?

Apart from that, a router with an external SIM-card stick may be a nice idea, if in the future I can replace the 4G stick by a 5G one. However, don't they have limited connectivity since they seem to have no external antenna?

I mean "public". What I get here in the Philippines is 100.107.191.38, which is from RFC 6598. Back in Russia, it was something from another private range, e.g. 10.142.0.102. Both of them are not connectable from the outside, even with DynDNS, because this is behind a provider NAT where you can't forward any ports.

Note: to check if you are getting a public or a private IP, you cannot use services like , because they show the IP address of the provider's NAT equipment, not of your phone. Please use something like Network Info II on Android, turn of WiFi, and look for the rmnetX interface.

does it mean that my requirement "guest network with limited bandwidth so that they don't suck up my data plan, and also, maybe with some ports blocked (like opening only HTTPS, HTTP, IMAP and SMTP ports)" can be met with any OpenWRT-compatible router?

If my 2 cents can help ...

For some months, I had a subscription for the 5G box from the French internet provider B....... , the hardware was a TCL Linkhub 5G (I do not recall the model, and I could not quickly find it in its webpage).

Although advertised for up to 1.1 Gbits down and 58 Mbits up, I had (of course) less than that, where I lived. Consider about 150 Mbits down and 35 Mbits up, ping about 40 ms. Overall, better than the ADSL subscription I had some years ago, but not worth a basic fiber subscription you can buy nowadays. Some pros and cons anyway, I can give more feedback if you are interested

OK, thanks to you guys, it looks like I've learned something new today (that's probably obvious to you:) ): on a 4G subscription, you can't make servers on your LAN accessible from the outside as easily as on an ADSL/fiber subscription. That makes the Cirrus device I mentioned above even more interesting, for someone who's very moderately a network geek:

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