< yourConnecString >  =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = < yourHost or IP > )(PORT = < urListenerPort > ))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = < your sid or serviceName>)
    )
  )

----------------------------------------------------------------------

BIOCHIP_CHIPDB2 =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = biochip.xxxx)(PORT = 1526))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = chipdb2.xxxxxxxx)
    )
  )
for the above entry...i would conect as
mag@itloaner1_local > connect dbadmin@biochip_chipdb2
Enter password: *********
Connected.
mag@itloaner1_local >