Device vendors provide man-machine interfaces in most network elements to allow operators and management systems to control these elements both locally and remotely with ease. Man-machine languages can be used by craft operators and in Operations Support Systems (OSS). Unlike most networking protocols, humans can compose and read messages these man-machine languages quite easily. This ease of use has benefited TL1 operators in terms of quick learning curve to familiarize with the TL1 operation commands.
Since a huge investment has already been made by companies to manage devices using the TL1 Protocol, it may not be practical to switch over to any other management protocol in the short term. Moreover, TL1 over TCP has gained tremendous popularity due to the in-built reliability of TCP communication. This has encouraged many optical equipment vendors to manage their optical devices using TL1. Another important reason for the popularity is that the standardized structure of the TL1 protocol messages, which is not specific to a particular device. This allows inter-operability in a multi-vendor environment.