CDMA Modems

[Tim Rose]

I am trying to determine which CDMA modems have been tested with Vision controllers. In the US, GSM is only used by AT&T and TMobile whereas CDMA is used by Verizon, Sprint, Metro PCS and others.

[Emil]

There was only one CDMA modem which was tested - more than 5 years ago. This modem is discontinued. Meantime, we found, that uspport of CDMA is very complicated. There are not SIM cards and the modem needs to be disposed to the provider to burn there the number. Usually the provider downloads there its own OS. Then - things which were working in Israel, can not working in Australia (or in Florida, if you prefer).

In this matter the things today are eve "worst". Israely provider, which hold CDMA network, "switched" to GSM. We are not able anymore to make any R&D with this network.

From other side - practically everywhere there is CDMA network, there is GSM coverage too. In tha last 2-3 years there is very, very rare request to support CDMA modems.

[Walkerok]

Hi Tim,

I meant to respond to this some time ago, but forgot about it. The easiest way to go is a GSM modem because some of the work is already worked out for you. But like you said onlt ATT and T-Mobile are GSM in the good ole USA. If you issue is that you can not get a usable signal with either of these companies then CDMA will be required. However, if your experience is like ours that ATT has no idea what a modem is, what M2M is, and what a static IP address is, then act like they are 3 year olds who no longer understand the english laguage then I would suggest that you go to a third party carrier of their data.

We use T-mobile for all of our modems, but we do not use T-mobile (this will make sense in a moment). Both ATT and T-mobile have contracts with third party companies that do know what they are doing and the tech is used nationwide for oveland trucking companies to keep track of truck data. The 3rd party companies will also be cheaper on the monthly plans. There are several, but we use a company called Jazz Wireless. If you put in a google search for m2m provider several companies come up. We personally stay away from ATT since they are much more expensive than what we have gotten from third party groups that use T-Mobile. The good news is wheather you pick one or the other you can use towers from both. So as long as one of them is available you will be ok.

Now onto the CDMA. Techinically, there is no reason whatsoever why a CDMA modem will not work with a Unitronics once it has been set up. You can get CDMA modems from many places (Multitech makes a very nice one). The CDMA modems are only able to be for one provider and before you buy you MUST gauranteee that the modem you are looking to buy is "approved" on the carrier network you are wanting to use and that the carrier will allow M2M connections. You can not switch carriers on CDMA modems ever and even if hardware says that it is "open" or "broken" the carrier will refuse or be unable to use it if it is not "approved". The hardest part is the setting up, and the carriers are all unprepared to correctly make M2M data connections because no one ever asks for them (or you can never find the one person in all of the carriers employee base that knows anything).

It will take a fair anount of work between you and the modem and you and the CDMA carrier to make it work, but you can make it work if you must. It will not be easy, but once you figure it out one you will be able to use the information over and over again. If you must go with CDMA I would start with a Multitech modem (they have units that are approved for Sprint, Verizon, and Aeris and specialize in M2M and may be able to help with the setting up process. They may have other carrier approvals but we don't use CDMA so I have not gone very far with this analysis.

Good luck

Keith

[Simon]

Hi Emil, I am glad you think of Australia when modems are being talked about :-) I hope one day we will have a perfect solution.

The complexity of setting up depends on what you are trying to do.

If it is just SMS you have a better chance of success. If you need data, then good luck.

I have found that GSM modems typically use a standard command set for SMS. However even subtle differences can be enough to prevent it working if the modem is not a standard type supported by Unitronics. My only attempt at getting a CDMA modem to work found they had used a completely non-standard set of commands for SMS, so it was a non-starter.

If you have a CDMA modem that uses standard commands for SMS then you may be able to make it work by modifying the AT commands in one of the standard modem configurations provided by Unitronics. If this works, you then need to document this extremely well to make sure you can repeat your success.

For data connections, I would follow Keith's suggestion and try to find a 3rd party re-seller who has expertise in M2M. They can then help with modem setup as well as assigning network access. You can run into several issues related to visibility of IP address, and segmented networks. Standard Telco helpdesks certainly have trouble with these types of concepts. You also find odd things like data not travelling between competitor networks. They can also change the rules to suit the majority (teenagers who want twitter and facebook on their mobile phones) and disregard the implications for M2M users. Sometimes the most suitable data solution is to put an ethernet card in the PLC and use an braodband wireless router with ethernet port.

I hope this helps.

[Hangfire]

I have been working on setting up some monitoring telemetry with Unitronics PLC's and gsm modems. We found the GSM modems very cheap and have a few of them. I started looking into which carrier we can get set up with and found out today that ATT is apparently taking down it's GSM network. Disregarding the fact that AT&T neglected to mention this, they were perfectly willing to sell us an account with GSM. Our telemetry plan is based entirely on SMS at the moment. Who is a good choice for GSM with data plans including SMS?

[Joe Tauser]

Hangfire-

You didn't mention where you are located so I Googled your IP and it came up Georgia, USA. I am in Missouri and use a company called Kore Telematics - www.koretelematics.com. I use the GSM modem offered by Unitronics and it has worked well.

Joe T.

[Simon]

Kore Telematics are now in Australia as well, that's exactly the kind of company I had in mind.

[Hangfire]

Thank you for your replies. I'm actually in Texas. I have spoken with the company Jazz Wireless Data (T-Mobile) today, that Walkerok mentioned and I'm somewhat shocked at the pricing difference compared to ATT and Sprint, and I found out that Sprint doesn't use GSM which rules out GSM modems with them anyway. A Sprint M2M rep actually referred me to T-Mobile. I appreciate the leads on Kore Telematics, I'll look into them.

To correct my previous post, it's now my understanding that ATT may not be taking down its GSM altogether, but they may be redistributing that bandwidth to the newer stuff. I don't know that for sure.

[Walkerok]

I'm glad you are on the short track to a solution. It is kind of amazing the monthly price difference with Jazz on T-mobile instead of the ATT offerings . Also Jazz has been very responsive to us whenever we had specific tower issues in certain parts of the country and has taken the initiative to get the correct T-mobile people in on the discussions. Also nice, is the low $1 fee for the static IP address. I have never used Kore Telematics, but I am sure they are good.

Keith

[Hangfire]

Walkerok-

What kind of tower issues were you having? I have gotten some sim cards in from Jazz and started testing our setup, and we have an issue where our device will respond to inbound texts but a device initiated text will not go through... They told us its an issue with ATT as we are connecting to an ATT tower near us. I hope this isnt a widespread issue!

[Walkerok]

I am not sure why you are not able to text off of an AT&T tower. Our issues have been with getting T-Mobile to change the MTU "maximum transmission units" to lower the size just a bit because it was causing a huge number of timeouts. In this case T-mobile had upgraded hardware and the settings were changed causing problems for us. it took a series of late night conference calls but everything was worked out. The other issues we have had are tower switching problems where we were approximately the same distance between a T-Mobile ans an AT&T tower and our unit was being confused by continuously swapping between the two towers. In that case we installed a two frequency YAGI antenna so that we could force one tower to have a much stronger signal than the other to stop the switching.

We have not had any issues sending or recieving texts. One thing we do when we have mystery problems like this is to make sure that it is not a hardware issue. If you go to Wallmart or best buy and buy literally the cheapest T-Mobile pre-paid phone you can find (we got our last one for $23.95). Install your SIM into that phone and see if you can send and recieve messages on the prepaid phone and taking any PLC and modem hardware issues out of the mix. Granted when you are on a AT&T tower you will be in a roaming mode, but you should be able to send and recieve texts no problem. If you can with a phone but not the PLC and modem then you have at least cut your diagnostic view in half by determiniung that for sure there is a SIM card to carrier issue or if there might be some kind of PLC/modem issue.

Keith

[Hangfire]

Thanks for your response Walkerok.

We have tested with an att prepaid card, it was actually what we first started testing with before choosing Jazz. I will look into trying a tmobile phone, i can also manually send a text with a computer in hyperterminal which is ugly but it works. Don't remember if i tried that yet. But the ATT card works flawlessly with our device....

[jweav2223]

We are attempting using a similar M2M provider by the name of Raco Wireless for data services on the Enfora modem. We've signed up for a 90 Day Demo program and ordered 3-4 SIMs to try out. In the middle of testing now and have come under the following issue. I am able to to Initialize the modem with no problem. When GPRS Register FB occurs it does to completion and gives me an IP Address (I've been told this is the Static IP Address). However this is not the Publicly Accessible IP Address to allow connection. The IP Address given is the one for Raco Wireless's network. I was told I would need to set up a VPN between Raco Wireless and our company to solve this. However that would only allow me access whereas if I'm building this for a company in North Carolina and we're in Oklahoma that doesnt help the customer out any in knowing what IP Address to "Call" for remote access. I was also told by Raco Wireless that these other M2M providers operate off a similar set up so going to see the same problem. However, it looks like many of you have been able to get operating smoothly. Would anyone care to email me steps on how to set this up? I'm rather new to this aspect of the Controller so bear with me. My contact information is jweav2223@gmail.com

[jweav2223]

Repost

[Walkerok]

Not wanting to call your particular service provider any names, but Im sorry, what they have given you is not the same thing as all other providers and it is not correct to say everyone else will have the same result. The static IP address you have been given is not a public IP it is a private IP which means that you will only be able to access it after you have connected to your providers VPN. This does not mean that it can not be done, but it is more difficult.

The provider we use is able to give us a public static IP so I can make connections direcly. I have never personaly tried to use a VPN to get to a private IP address so I am not able to help in determining what steps to take to make it all work, however I am sure that it can work. We took this approach a long time ago when we were first trying to use a Sweedish product that plastered their companies name all over everything when going through their VPN. We were not interested in sending our customers to get a sales pitch from the third party VPN so we worked our way arround them.

I will have to deffer to anyone else out here that has done this using a private IP address with the need to go through a third party VPN to get there. Getting to the VPN should be easy enough but I am usure what to try after that to get it to work.

On the plus side, being under a third party VPN when sending emails out would be easier because the PLC does not have the ability to use SSl encryption needed for almost every server in the world to accept an email. In the case of being behind a VPN the VPN will trust all communications from one of its own static IP addresses and then will pass your email on to its finall recipient having added the needed legitimacy for other mail servers to accept the email.

We have a server that is ours that we tell what static IP addresses are OK to recieve emails from and then we just pass everything on from there and the rest of the mail servers accept our in house email server as being legit.

Keith