A.4G B.GPRS C.CDMA D.以太網(wǎng)
A.測試終端485A(B)和電表485A(B)電阻為0 B.測試485端口電阻為0 C.測試485端口電壓為0 D.測試終端485A(B)和電表485A(B)電阻不為0