The present invention discloses a method for carrying out a loopback test in a data communication system having a first data communication station, a second data communication station and a transmission line connected therebetween. The first data communication station transmits a succession of a first...http://www.google.es/patents/US4271513?utm_source=gb-gplus-sharePatente US4271513 - Method and apparatus for carrying out loopback test
Method and apparatus for carrying out loopback test
