This is peter from china skyline telecom
We are professional voip gateway manufacturer
We have E1 media trunking gateway (connect with E1 media lines ) fxo gateway(connect with pstn)
e1 and fxo all no need sim card,so no sim blocking
If you have any questions,please contact me
my skype:chinaskylinepeter whatsapp/phone:008618682039136
Peter Rao