我在测试一张SIM卡的联网状态时，反复发现卡下线，又上线，一直都是这样，不知道是什么问题导致，下面是我获取的AT指令接口返回的结果，请高手帮忙分析一下，谢谢。
Got 24 bytes:
[
+CGEV: EPS PDN ACT 5
]
Got 33 bytes:
[
+NITZ: 19/01/04,02:17:40+32,0
]
Got 28 bytes:
[
+CGEV: EPS DED DEACT 1,5
]
Got 24 bytes:
[
+CGEV: EPS PDN ACT 5
]
Got 33 bytes:
[
+NITZ: 19/01/04,02:17:50+32,0
]
Got 28 bytes:
[
+CGEV: EPS DED DEACT 1,5
]
Got 20 bytes:
[
+CGEV: ME DETACH
]
Got 24 bytes:
[
+CGEV: EPS PDN ACT 5
]
Got 33 bytes:
[
+NITZ: 19/01/04,02:18:06+32,0
]
Got 28 bytes:
[
+CGEV: EPS DED DEACT 1,5
]
