Roco 10833 HO RO z21start Base Digital Set (DCC) Contents: 1 item, Manufacturer: Roco. The Z21 is a modular system. Start with Z21 start-center and Z21 multiMAUS. Upgrade with WLAN router and activation code, article no. 10814, thus use of smartphone, tablet PC, Z21 WLANMAUS and computer (software-supported model railway control) is possible. If you have your own WLAN router and are familiar with WLAN networks, the activation code 10818 is sufficient for the above mentioned upgrade.