The MADI interface (AES-10) allows the transport of up to 64 mono channels in either direction. MADI is
a common method for connecting two different systems (TDM and AOIP) or gear from different
manufacturers (i.e. WNIP to an intercom or other routing or mixing system). The 64 channels may be
paired off into either stereo or even 5.1 signals depending on the user interface.
For MADI to operate correctly without clicks or pops, both sides must be running at the same sample
rate and synchronized to the same reference. This is usually done in a TV installation by taking the DARS
(AES-11) signal out of the house Master Clock/Sync Pulse Generator and feeding it to a AES DA. The DA
can then feed sync inputs on each system fitted with a MADI interface.
For Wheatnet IP, the DARS reference is fed to AES Input 8 on any Blade with AES inputs. Other options
are the DARS input on a HD-SDI Blade. WNIP can even be synchronized from the MADI input but this
method should only be used as a last resort. In Navigator select the INFO tab and use the Clock Master
Info section to select the desired sync source and sample rate.
On a Wheatstone TDM system DARS will connect to the DARS sync input on either the Wheatnet or the
Gibraltar frame with the system CPU’s. Dipswitch settings determine if the External AES sync signal is
used. Consult appropriate documentation for details.
If you can't sync both sides with DARS, then the next best option is to sync the Wheatstone side or the
other MADI device from the MADI Input signal.
Word Clock is a square wave at the sample rate frequency; usually 44.1kHz or 48 kHz. Word clock is not
the same as DARS and can not be used to synchronize your Wheatstone system.
Many MADI devices allow for device connections using optical fiber. The original spec called for multimode fiber and SC connectors. Many modern devices deploy SFP interfaces. The flexibility of SFP’s
allows for using multi-mode or single mode fiber usually on LC connectors.
Regarding SFP's - the MADI interface is only 100Mb/s. It is best practice to use SFP's from the same
manufacturer for both ends to ensure that the tx/rx specs match. Not all SFP's are the same. Some reclock
the signal and were designed for Gigabit Ethernet. Ideally you would use < 200Mb/s SFP's that
simultaneously support FDDI/SONET, etc.
We've successfully used Finisar FTLF1217P2BTL SFP’s with multi-mode fiber.