Call center over sim cards

Hi, i’m trying to set up a call center for a new client. I’ve been about a week searching an answer on the subjet withoug being able to find out what exactly I am going to need. I have worked many times with linux but never with asterisk or the hardware involved.

The call center will have around 30 positions running over SIM cards, and the Telephony Company can provide me of “telulars” (i don’t actually know how if it’s the right term in english).
I found out some things about Asterisk, but I still don’t know which hardware is neccessary.

My idea is to connect this telulars to each telemarketer’s pc, and I mainly need them to be able to make calls from some kind of interface(which from what i’ve read, FreePBX has).

I hope you can help me out. Thank you, and I apolagize if the question is too specific or too easy, but I haven’t been able to figure it out.

Telular is the brand name of a device which works over a celular network to provide the equlivant of a single POTS line to a location. Some even provide a data connection for internet access.


So you will need one of these for each trunk that you plan on having.

Since these provide an FXS port, you will have cards or a channel bank with FXO ports to get into your phone switch.

There are also a number of devices which use multiple SIM cards to allow a SIP connection directly to the server.


Ok, I think I get it. Thanks a lot for your answer.

Now is there any way I can connect this devices to each pc and make outlines individually from there?
The thing is that for those 30 terminals I won’t be spending less than u$s 1000, and my client totally refused to do that.

The only cheaper solution i figured out was that. Since it’s a sales only call center (not customer service will be running there) I won’t need to queue incoming calls and the like. So the main thing i need asterisk for is calling from the PCs and record those calls.

Do you know any way to do that?

Thank you very much again

My first comment is I would run, not walk from a client that balks at $1000 for 30 lines of anything. You can’t make money on cheap customers.

Can you get reliable SIP service in the location?

Lastly, before asking in the FreePBX forum if it can do something, spend some time in our wiki so you know what we do here.

My first comment is I would run, not walk from a client that balks at $1000 for 30 lines of anything. You can’t make money on cheap customers
It was impossible for me not to laugh pretty hard at that xD (I’ve been facing that fact for over two years with him on other matters).

Lastly, before asking in the FreePBX forum if it can do something, spend some time in our wiki so you know what we do here.

I’m sorry, but since it was something that HAS to work well i was kind of afraid of trying to set it up by myself not knowing if it was actually possible to do it.

I do should be able to hire a good SIP service. If i were to do that the only thing i would need would be the FXO ports on the server for those 30 positions, wouldn’t I?

Thank you for your answers once again

1 - I am glad you laughed, it was meant to be funny. And provoke thought. I hardly know all the circumstances so take it with a grain of salt

2 - SIP works over IP, no analog ports needed at all. Just a reliable IP connection to the SIP provider.

You are going to also have to check into the capacity of the wireless network you will be utilizing the fixed wireless units on. I have an extensive background using telular equipment in the past (launched a CLEC years ago where we built an HFC network, and complimented that with a 1900 MHz PCS network where we competed using fixed wireless in the competitors landline network,) and although capacity and bandwidth has grown, still putting 30 units in one location is going to be an issue. In the past I was able to overcome this by adding an additional capacity on the wireless network, but it’s likely that your carrier is not going to pop for even a micro cellular site, especially if the customers budget is only 1k per month.

Preston, I was thinking the same thing. 30 more or less continuous users would stress most cell sites. I don’t know what their working hours would be, but if they worked 8 hours a day, 5 days a week, the aggregate usage could exceed a quarter million minutes per month. (Check my math…8 hours x 60 minutes x 20 days x 30 phones).

Tellular units are going to cost around $500.00 each. Not to say it cant be done, but in addition to the technical issues , capital costs, and the airtime costs, this could be a very expensive proposition.

Is PRI available? Is sufficient bandwidth bandwidth available, and is there a reliable SIP provider available?

. . . . and does the kamtraz yet know that he can use softphones on his user’s desktop to connect to Asterisk, and then to his lowest cost outbound routes. I note that Scott suggested going to the wiki first, I hope kamtraz has taken that wise advice.

Thank you, sorry I didn’t answer before.

Actually, I never thought about the stress on the lines, just didn’t realize that could happen since I already saw a call center working the same way.

At any rate, the thing is that our telephony company can provide my client his telulars for free when we hire their service, with a cost of $0,03/min and most SIP providers costs a lot more than that.

I don’t know, I think I think I’ll just leave it to someone that know more on the matter.

I am truly grateful for your help, but I think I’ll just try to learn something more before assisting a client on asterisk.

What you want to do from a purely Asterisk/FreePBX issue is really pretty simple. It’s the environment, I believe, that most of us feel uncomfortable with. Most of us have used the cellular network as a backup, but setting them up as a 30 trunk primary is a bit out of my comfort zone. The cost of $.03 a minute may sound cheap, but in fact, based on the earlier hypothetical calculations, that would still be in the thousands of dollars.

Good Luck!!!


If I understand correctly it is your company who will be providing the client the outbound service. Can you instead of that provide the client with direct SIP connection to your Telco with the required capacity of 30 lines?