Hello Murali, yes, ALE is a general SAP tool to send data over. But you can also setup as background job, by creating IDOC in the sending system and receive them in another.
RBDMIDOC (create IDOC)
RSEOUT00 (send IDOC)
RBDAPP01 (receive IDOC)
As for specification transfer, the message type and IDOC type will be as below
Message Type: SUBMAS
IDOC: SUBMAS02
But since we are building substance based on phrase/phrase set/characteristic/class, we need to make sure they are also sync up or send over. Otherwise it you may see errors.
To setup ALE link will be a difficult task, you need the help from SAP basis team to work together, such as WE20, SM36 and so on.
By the way, there is also option for serialization. You can have a look there for ALE.
Take care and good luck