If an 256K bits EEPROM is not inserted in the U2 socket, UCM/GSM4 will behave like UCM/GSM3 ie it will not send Help messages and status messages by SMS
Please take not of known bugs below
When 'the H' is shunted, the network strength is wrongly reported in Comfigurator and on-board LEDS shown are wrong. However, if the UCM/GSM4 is de-selected and reselected again, the strength reported in Comfigurator is correct.
When UCM/GSM loses communication or communication restore, the second phone number in Security Mode tab is not dialled out. Instead, the first phone number is dialled twic
If no feedback type assignment in Control Item, the reply SMS has missing "Control Group" and "Control Item" field.
Note that non-english alphabet is not supported yet eg Chinese, Japanese, Arabic
Incoming SMS commands in other languages may be accepted if the message has only (, numbers and ) characters