G.703 NTU Connections

[Curiosityx]

Greetings one of our customers have recently had a leased line installed, we asked them to present the connection on X.21 but have presented it on G703 instead as per the image below.

I now require a Balun to connect our router via Ethernet to the BT NTU, ive never had to spec the above before and am slightly unsure of which cables/connectors are required, currently im looking at the products below.

http://www.blackbox.co.uk/solutions...doc=mt242a-m&tx=WAN&sx=G.703/G.704 Converters

G.703 Balun 2.048-Mbps, Female

Could someone help me the coax cable needed between the NTU and the "Black Box"? I believe that the connection then from the "Black Box" to the router is Rj45?



Regards

 

[Curiosityx]

so those boxes do actually convert between whatever protocol is used on the coax side and ethernet on the twisted pair side? that's kinda cool! i thought they literally just changed the presentation from coax to twisted pair in terms of form factor, not including signalling!

when it comes to coax i've worked with both 50 ohm and 75 ohm... it's been a while, but from what i remember we used 50 ohm stuff for old ibm mainframe stuff and 75 ohm for telephony... so you might want to make sure the coax is 75 ohm? i can check with one of our telephony guys in the office tomorrow if you want confirmation?

From what i can make out it takes a 75ohm balanced or unbalanced coax connection and converts it to a 120ohm Rj45 connection for termination on an NTE

 

[Curiosityx]

So on your router you simply have an rj45 twisted pair WAN interface, as opposed to an actual Ethernet interface?

Well all has been resolved to an extent, were going to have the presentation changed back to X.21. Otherwise i imagine we would have had to install an E1 interface to accommodate the connection.