G.703 vs. G.704 modules

[vitute2006]

Hi:

I need to add an E1-PRI interfase for a Cisco 28xx to support backup data calls through an ISDN cloud.

I´m confused about what module to choose (VWIC-1MFT-E1 (G.704 framed) or VWIC-1MFT-G703 (unframed)).

1) What is the practical difference between both?

2) For VoIP, I normally choose the VWIC-1MFT-E1 module plus PVDMs, when should I use the G.703 module?

[ssoberlik]

The matrix mentioned in the document http://www.cisco.com/en/US/products/hw/routers/ps274/products_tech_note09186a00800b6e0f.shtml shows the differences between the modules VWIC-1MFT-E1 and VWIC-1MFT-G703 .