Phone1--PBX(Erricson)---(2BSV)AR28-11-----（IP network）－NCX(softswitch)－－PSTN(GSM)--phone2(Mobile phone)
2, Before it is cisco equipment in the place of AR28-11 and it work fine.After replace AR28-11, there is no any voice after call from phone1 to phone2 except busy tone.
From debug of isdn we can see infomation of "Assigned TEI is wrong!"
There is no problem from phone2 to phone1.
*0.9725901 BRA-site Q921/4/Q921_Debug: Bsv1/0
Assigned TEI is wrong!
1, From debug we can see the value of TEI is 0 which is send in PBX Q921 message SABME. And our AR28 router use dynamic TEI distribution which value range is 64-127. That's the reason it can't establish call correctly and print error message of " Assigned TEI is wrong!"
2, Howerver, there is another way reach this target. Config BSV as p2p mode which command is "isdn link-mode p2p" under BSV card view.
The default TEI will change to 0 which is common value in usage.
3, After we change to P2P mode, the call is normal for both direction.
1, First check link layer. The link lamp is light.And the interface of BSV is up. So we can remove the possibility of physical layer such as wrong cables.
2,We can also remove PBX problem as it work fine with cisco router.
3, Compare Cisco configuration. We can find they have one special configuration which is "isdn static-tei 0". Also from debug we can see the error message is "Assigned TEI is wrong!". So we suppose it shoule be reason of TEI.
4, Check user manul, we can't find some way config static TEI on AR28 router.
Change P2P mode, the default TEI will be 0. And this way solve this problem.