小知识：
What is +CMS, and +CME Errors?
+CMS Errors are returned from the SMSC. +CME Errors are generated by the GSM device firmware.

CMS是 短信中心SMSC的返回错误；CME是设备返回的错误。


Here are the most common CMS errors:

CMS ERROR: 1 Unassigned number
CMS ERROR: 8 Operator determined barring
CMS ERROR: 10 Call bared
CMS ERROR: 21 Short message transfer rejected
CMS ERROR: 27 Destination out of service
CMS ERROR: 28 Unindentified subscriber
CMS ERROR: 29 Facility rejected
CMS ERROR: 30 Unknown subscriber
CMS ERROR: 38 Network out of order
CMS ERROR: 41 Temporary failure
CMS ERROR: 42 Congestion
CMS ERROR: 47 Recources unavailable
CMS ERROR: 50 Requested facility not subscribed
CMS ERROR: 69 Requested facility not implemented
CMS ERROR: 81 Invalid short message transfer reference value
CMS ERROR: 95 Invalid mes