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DS3 Fiber Optic Modem

I need to extend a demarc for a T3 for ~= 1 km and would like to use a FOM solution.  I have both SM and MM fiber available and I think I would like to utilize the MM given that this is a relatively short distance.  SNMP fault polling and trap generation would be a plus but this isn't a necessity.  Does anyone have any experience with this?  What should I look for - any gotcha's here?  Are there solutions available that provide hardware redundancy? 

Has anyone used any of these that they would recommend? 

As you can probably tell from all the questions I don't have any experience with a T3, so any advice is appreciated!



paolo bevilacqua
Hall of Fame Master

Can't you put a router where the service is delivered, and do the rest over IP/fiber?

That will make it a lost easier, cheaper.

Well I could, but the purpose of the extension is to put the router in another building.  The environment at the demarc is not the best suited for routers and it is not an ideal location in the campus network for one either.

I don't have direct working experience with the DS-3 media converters. 

However, what I have typically seen is a lack of redundancy options for module or fiber line failures.  Adding this functionality with outboard equipment (optical and electrical swithes and additional media converters) will add cost and complexity.  Most vendors have options available for SNMP management.

If you want more redundancy, you typically have to move to a transport system (aka 15310 or other); but this increases the cost and complexity of the installation. 

One example is Transition Networks ION Chassis with DS3/T3 module.  


You can use the RAD modem like this to extend the T3  and MM solution works for 2.5Km . But you need in pair as you you can see in picture.

For redundancy you can buy 3 modem means 1 spare. You have only 1 DS3 interface so that is Singel point of failure. How can you feed a single Ds3 circuit to 2 different modem for redundancy. We only think about providing redundancy for box but there are chances your DS3 interace can have problem which is not redundant, power supply is not redundant etc.

If you have budget then can opt for some PIZZA type SONET/SDH box STM1/OC3 boxes. Then you can see if they have dual power supply etc.

If going for complex solution then will you be able to support yourself as you have no idea about T3. RAD modem are easy to use