I try to make external IVR on E1 Siemens Hicom Trunk using Sangoma A102. E1 port connected to Telco works without any problem. E1 port connected to Siemens doesn't start because is restarted as below. Where I have to look for the reason (and solution) of this problem ? No. Time Source Destination Protocol Info 1 0.000000 Remote User Local Network LAPD U P, func=SABME 2 0.000528 Local Network Remote User LAPD U F, func=UA 3 0.000717 Local Network Remote User Q.931 RESTART 4 0.099999 Remote User Local Network LAPD S, func=RR, N(R)=1 5 0.150849 Remote User Local Network Q.931 RESTART ACKNOWLEDGE 6 0.151372 Local Network Remote User LAPD S, func=RR, N(R)=1 7 2.997662 Local Network Remote User Q.931 RESTART 8 3.091613 Remote User Local Network Q.931 RESTART ACKNOWLEDGE 9 3.092027 Local Network Remote User LAPD S, func=RR, N(R)=2 10 6.997654 Local Network Remote User Q.931 RESTART 11 7.100010 Remote User Local Network LAPD S, func=RR, N(R)=3 12 7.113235 Remote User Local Network Q.931 RESTART ACKNOWLEDGE 13 7.113565 Local Network Remote User LAPD S, func=RR, N(R)=3 14 10.997071 Local Network Remote User Q.931 RESTART