The rs_set_quoted_identifier function string is added to set the DSI connection to Adaptive Server and Microsoft SQL Server.
When dsi_quoted_identifier is set to on, Replication Server sends the rs_set_quoted_identifier function string to the replicate database as part of the connection configuration when the connection is established. Replication Server uses this function string to allow quoted identifiers to be sent through the connection.
See Replication Server Reference Manual > Replication Server System Functions > rs_set_quoted_identifier and Replication Server Administration Guide Volume 2 > Customize Database Operations > Working with Functions, Function Strings, and Classes > Summary of System Functions.