 
                            it conforms to ITU-T technology standards and the national technology system light synchronous transmission network. It can test network error code, jitter, pointer, bolt, insertion/drop, and other parameters of SDH/PDH. The test set is versatile. It can be widely used in the fields of development,
| Error type | single | ratio (10-N) | 
| frame | √ | N frame in the four frames (N=1~4) | 
| B1,B3,HP-REI,HP-IEC | √ | N=4~9 | 
| B2,MS-REI | √ | N=3~9 | 
| BIP-2,LP-REI | All errors | / | 
| Open and cancel bit error | √ | / | 
