dbGetInfo, it's possible to determine the DLL that is used for the ODBC connection. It is sqlsrv32.dll. library(odbc)
sqlServer <- dbConnect(odbc(),
driver = "SQL Server" ,
server = Sys.getenv("COMPUTERNAME"),
database ='tq84_db'
);
dbGetInfo(sqlServer)$drivername;
#
# "SQLSRV32.DLL"