Hi Friend,
1) The first command is used to compress startup configuration files, use the service compress-config command in global configuration mode.
After you configure the service compress-config command, the router will compress configuration files every time you save a configuration to the startup configuration. For example, when you enter the copy system:running-config nvram:startup-config command, the running configuration will be compressed before storage in NVRAM
Check this link more details
http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124tcr/tcf_r/cf_06ht.htm#wp1035002
2) For second command is to hide addresses while trying to establish a Telnet session, use the service hide-telnet-address command in global configuration mode
When you attempt to connect to a device, the router displays addresses and other messages (for example, "Trying router1 (171.69.1.154, 2008)...)." With the hide feature, the router suppresses the display of the address (for example, "Trying router1 address #1..."). The router continues to display all other messages that would normally be displayed during a connection attempt, such as detailed error messages if the connection was not successful
Check this link for more details and usage guide lines for this command
http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124tcr/tcf_r/cf_06ht.htm#wp1035321
HTH, if yes please rate the post.
Ankur
