The Virtual Tele Type (VTY) has the concept of nodes and commands. This chapter lists all nodes and the commands that are available within the node. Each command can consist out of several words followed by a variable number of parameters. There are common patterns for the parameters, these include IPv4 addresses, number ranges, a word, a line of text and choice. The following will explain the commonly used patterns. Pattern Example Explanation A.B.C.D 127.0.0.1 A IPv4 address TEXT example01 A single string without any spaces, tabs .TEXT Some information A line of text (OptionA|OptionB|OptionC) OptionA A choice between a list of available options <0-10> 5 A number from a range The application is configured through the VTY. For configuring a system one needs to enter the enable node and then enter the configure terminal command. Then the configuration can be made according to the available commands. After the system has been configured one can use the write command to write the new configuration to the configuration file. The new file will be used after the application has been restarted. The following table lists the TCP port numbers of the VTY for the various Osmocom GSM related programs as used on sysmocom products: Port Number Software 4240 osmo-pcu 4241 osmo-bts 4242 osmo-nitb, osmo-bsc 4243 osmo-bsc_mgcp 4244 osmo-bsc_nat 4245 osmo-sgsn 4246 osmo-gbproxy §ions-vty;