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FXS port used with Cellular Basestation Ericsson W35


A few years back, when CCM 4.3 was around, I had to convert a celluar type basestation into an analog gateway for some IP phones on our companies network.  This was out in Iraq, so land lines were out of the question.

I got this working, but I believe I was using a MC3810 w/ an FXS port and running H.323. 

For my lab, I ordered an Ericsson W35 cellular base station and bought a cheap prepaid SIM card to put in it.  I figured it was another was to get access to the real PSTN.  I am trying to get this to work on a 2801 running CME.  The basestation is connected to an FXS port.  I swore I used an FXS port in Iraq, but I am starting to think that it might of been an FXO (because I cant get this working).

Basically, my goal is to have all my IP phones use it as an outbound gateway, and also users from the outside can call the number assigned to the SIM and it can be translated to hit a hunt-group or however I want it to work.  The part I am having trouble with is just getting it to work with inbound or outbound calls.

I believe the problem boils down to is that the FXS port is always in an Off-Hook status because its connected to the basestation.  I have tried different signaling methods, connection methods (tie-line, trunk), etc.  I cant get it to work.  I get a fast busy as soon as the IP phone finishes dialing the number because that port is already Off-Hook and busy.

Is there a way to accomplish this with an FXS port?  There isnt any kind of configuration methods on the Ericsson device, I already looked at the web gui and its all very basic.  It works fine when I plug an analog phone directly into it.  But when I plug the line into an FXS port on the 2801 I cant get it to work.

Any ideas for configs?

5 Replies 5

paolo bevilacqua
Hall of Fame
Hall of Fame

The cellular interface is most likely FXS, meaning you have to use an FXO. That should be indicated in its documentation.