不能将同一 CID 注册两次，道理很简单，

当别人打这一号码，which provider handle your call?
so settings for line2 should be:
registration: NO,
ans call without registration: yes,
call without registration: yes,
By the way you can use GoogleVoice# as your CID to voipdiscount. this is bullet proof tested.

after update the info for line2 should be: offline.