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Community Member

T.37 for dummies... nearly there

Hello, I am trying to get a grasp of how t.37 Off Ramp faxing works. We have OnRamp working fine, where by a dial-peer is matched to an incoming fax number and passed to a mailbox. How does it work in the reverse?

If I put in the to field of the mail client, how does Exchange know to relay this message to the router (3845)? Where does the address mail domain name come from?

Here is my config -

fax receive called-subscriber $d$
fax send transmitting-subscriber $s$
fax send left-header $s$
fax send center-header $t$
fax send right-header Page: $p$
fax send coverpage enable
fax send coverpage email-controllable
fax send coverpage comment NZ Cover Page
fax interface-type fax-mail
mta send server port 25
mta send subject "Facsimile Transmission"
mta send origin-prefix Company Fax
mta send postmaster
mta send mail-from username CompanyNZFax
mta receive aliases []
mta receive aliases
mta receive aliases
service fax_offramp flash::app_faxmail_offramp.

dial-peer voice 8888 mmoip
service off_ramp out-bound
information-type fax
incoming called-number 77....... - Can you explain this please, is the router waiting for exchange to relay a number with 77 prefix then fax number?
image resolution standard
dial-peer voice 8889 pots
max-conn 10
destination-pattern 77.......
port 0/0/1:15
prefix 77

Thanks in advance


Community Member

Re: T.37 for dummies... nearly there


The easiest way to map the cisco router IP address and it's DNS name ( is by editing hosts file in c:\windows\system32\drivers\etc on your Exchange Server.

It is possible to avoid intermediate MTA (e.g. Exchange) by using software like facsBridge T37FSP . This software also renders TIFF files as cisco-compatible.

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