Nintendo released a modem peripheral called Famicom Modem. See voice modem command set for more details on voice modems. Transparent modems operate in a manner similar to their phone line modem cousins. It came with a 56K modem and 10/100 ethernet. A dialup modem was never released for NES. Fritz!Box devices with an integrated DSL modem come in three versions. The customer end of the connection consists of a terminal adapter or "DSL modem". Similarly, battery-powered routers may include a cellular Internet radio modem and Wi-Fi access point. HFC connections use a DOCSIS cable modem as their NTD. The game is also playable via null modem connection. The 12-month plans came with a USB modem (or dongle) for free. The firmware for the cellular modem on the phone is proprietary. It does this by encrypting data flows between the CMTS and the cable modem. There is also an option for a cellular modem and an internal eSIM module. The ADB port remained, as did the option for an internal modem.