Quintum with asterisk

Hi, I have a quitum tenor dx2030 and asterisk at our office. I have able to setup the T1/E1 of the quintum dx2030. Calls are being passed to our switch(Nortel). When I dial the the handset number i was able to hear a ringback on the sip-phone that is registered to asterisk. But my problem is that I cannot hear some ringing on the handset. Below is my voip call flow. Please help on this one, I really needs some help. By the way I’m using a R2 signalling from the Philippines. Thanks

sip-phone-asterisk–>quintum–>Nortel switch–>handset

Best Regards,

Best to read the troubleshooting section here, as there is really not enough info to go on in your post.