from my working expierence the soft switches usally work fine for fax/modem/cc machines if you are going tdm all the way thru. what some lecs/clecs are now doing is since these soft switches are voip cabable they are starting to trunk calls out via sip and we all know modem type calls don't work via voip. there are ups and downs to both the cost of ip/ethernet to transport calls is much cheaper then your standard sonet type network to setup full tdm. down side is you loose your modem type calls. it basically comes down to picking your evil cheap transport and modem wont work or expensive transport/equipment and modem will work. i guess it comes down to the companys business plan.

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