Hi:
This is peter from china skyline telecom
We are professional voip gateway manufacturer
E1 gateway it's no need sim card voip gateway,you can talk with operator for buy media lines
use e1 gateway,you can get TDM or cli route and cost just like ncli
We have 1/2/4 E1 gateway
If you have any questions,please contact me
My skype:chinaskylinepeter whatsapp/phone:008618682039136
Peter Rao