Bars n. 条
a bar of soap
a chocolate bar
I have no bars on my cellphone.
I only have one bar on my cellphone.
I have no signal on my cellphone.
Reception n. 信号接收效果
The phone reception is really bad in the mountain.
No service 没信号
Suddenly I’ve got no service on my cellphone.
Not in service 停机/不在服务区
Sorry. The number you have dialed is not in service.