If your Samsung Galaxy S5 may not find or be able to connect to a specific 5Ghz wireless network, you may want to check which channel the network is operating on. The S5 has problems when trying to connect to DFS-channels (Dynamic Frequency Selection).
DFS-channels are basically every channel from channel 52 and up. Try setting your AP to a channel between 36-48 (inc.), and then try reconnecting your S5.
By default, when using a Telenet address on your smartphone, the Telenet mailserver (uit.telenet.be will not accept messages if they're not sent from within the Telenet network (e.g. when using Proximus, Mobistar or some other ISP or cellular operator).
You can resolve the issue by adding SMTP authentication to your outgoing mailserver settings. Simply add your username and password, and you will be able to send mail using Telenet SMTP.
Here are the MMS settings for Proximus (a Belgian carrier):
iPhone users: the maximum message size has to be entered as 300000.
Use these to set up mobile internet on your device:
Try downloading octy's GPSopt application. It's available free of charge at Google Market.
It resolves the slow signal acquisition of the Samsung's GT-i5801 (perhaps on other phones as well). I use it together with GPSstatus (also available at Google Market) and no longer have GPS signal issues.
Lifehacker published a really interesting howto, explaining how to install Android on your iPhone in six easy steps: