на Астериске нумерация 25хх ...
попробовал позвонить на 2600 (26хх- не используется ни на Nec ни на Астериске)
прописав предварительно:
7600>2600:400
7601>400:EXT
итог тот-же...NEC возвращает "504 Server Time-out"
aster.host.sip > 10.7.200.2.sip: [udp sum ok] SIP, length: 815
INVITE sip:2600@10.7.200.2:5060 SIP/2.0
Via: SIP/2.0/UDP 10.7.200.23:5060;branch=z9hG4bK5267dc6f
Max-Forwards: 70
From: "2500" <sip:2500@10.7.200.23>;tag=as29c5e464
To: <sip:2600@10.7.200.2:5060>
Contact: <sip:2500@10.7.200.23:5060>
Call-ID: 4f75c31822e025d7682656ac13b164d6@10.7.200.23:5060
CSeq: 102 INVITE
User-Agent: AsteriskPBX
Date: Wed, 21 Aug 2019 14:18:42 GMT
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH, MESSAGE
Supported: replaces, timer
Content-Type: application/sdp
Content-Length: 262
v=0
o=root 1816270396 1816270396 IN IP4 10.7.200.23
s=Asterisk PBX 13.28.0
c=IN IP4 10.7.200.23
t=0 0
m=audio 15902 RTP/AVP 8 0 101
a=rtpmap:8 PCMA/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=maxptime:150
a=sendrecvпотом идет Trying
и....
17:19:02.314339 IP (tos 0x0, ttl 64, id 64587, offset 0, flags [none], proto UDP (17), length 320)
10.7.200.2.sip > aster.host.sip: [udp sum ok] SIP, length: 292
SIP/2.0 504 Server Time-out
Via: SIP/2.0/UDP 10.7.200.23:5060;branch=z9hG4bK5267dc6f
From: "2500" <sip:2500@10.7.200.23>;tag=as29c5e464
To: <sip:2600@10.7.200.2:5060>;tag=252d5d5d7d170-236
Call-ID: 4f75c31822e025d7682656ac13b164d6@10.7.200.23:5060
CSeq: 102 INVITE
Content-Length: 0