You need to configure the MD to accept the connection and the phones to receive SMS. I suggest that you look it through in Alex. This is the basic from Alex:
6.1 Initiation of a message service connection
General
A message service centre connection is initiated by assigning it a directory number and an I/O device.
Prerequisites
The I/O device should be initiated with the command IOEQI . See command description for I/O DATA, IO.
The incoming and outgoing ports should be initiated with the command IONCI . One call of IONCI with parameter USER=SMSS and LPORT value. A second call of IONCI with parameter USER=SMSC, IP-address and RPORT value. See command description for I/O DATA, IO.
The directory number should be initiated with the GEDII command. See command description for GENERIC EXTENSION, GE.
The SMS service centre number should be initiated with the command CXSYI . See command description for CORDLESS EXTENSION, CX.
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Execution
Key command MSCOP to verify that no other connection towards a message center is initiated.
Key command MSCOI with the proper parameters to initiate the connection.
Key command MSCOP to verify the result.