We have CUCM 7.1 and unity express 7.1 in a Bank setup, customer is asking for fax solution now, they are having 250 extension, every one should need Fax number with same DN, the Fax should be send/receive as Email attachement, please let me know solution for 250 user fax solution as email.
You can try fooling around with T.37 but I would recommend against it.
The correct way to do this is with Sagem-Interstar Xmedius Fax. Everyone who uses this product loves it. You can run it on an AXP blade within an ISR or on a x86 server. Whatever you do, DO NOT buy the Cisco (Captaris RightFax) product. It is horrible by comparison to Xmedius.
I'll tell you now that single-number for fax/voice is problematic. You have to do it through a TCL script on the voice gateway. It's messy, not perfect, and adds delay for anyone trying to call and speak with the individual. Save yourself a lot of hassle and just buy the additional DIDs.
Here are the TCL scripts if you want to look into T.37 or the single number for faxing: