Question about connecting voice gateway to PBX?

[kobchai7037]

Hi,

I have some problems understanding the way to connect voice gateway's ports such as FXS, FXO, or E&M to PBX. I have read 2-3 books about cisco voip but none of them talking about the ports of PBX that voice gateway will connect to.

All book will say that FXS provides dial tone so it must be plugged into endsystem such as telephone, fax machine. FXO must be plugged into PSTN or PBX.

I just have a chance to work with a company that is providing the installation of voip.

They plug both FXS and FXO ports to PBX. FXS to PBX's CO card and FXO to PBX's extension card.

I really can't find the information about this from anywhere. It would be really appreciated if anybody could explain this to me or give me the link that can explain about this.

thank you

[jtufail]

Well as you already read through the books the Analog card that can provide a dial tone is the FXS card and hence all analog devices are plugged into FXS interfaces.

You can think of your phone/fax machine as FXO end. For FXS FXO set up to work there must be one side to provide a dial tone. When you plug in your honme phone in to the jack you are connecting your FXO device to the FXS port that the telco is providing.

A PBX can have both FXO and FXS ports, just as the router can support both ports on one platform.

Maybe the following URL will help.

http://www.cisco.com/en/US/products/hw/modules/ps5365/products_data_sheet09186a0080191d41.html