The Pi Zero only has a micro USB socket, requiring the use of an adapter to connect an Ethernet cable.

Is there any reason I can't use something like [this cable](http://www.ebay.co.uk/itm/NS-PRO-SERVICE-BOX-SAMSUNG-S5-UART-RJ45-UNLOCK-UNLOCKING-FLASHING-CABLE-/121693014776?hash=item1c55780af8:g:0ysAAOxyVLNSsLQC), or even attempt to make my own with some old CAT5 and a spare phone cable?

Would the adapter need any kind of chip on it?