Base camp: 00 43 664 763 0255
Top camp: 00 43 664 582 5229 - incoming calls and texts only.
Top camp: 00 43 664 871 6782 - what it uses to send texts and make calls (from 2018)
After many years of using complicated radio systems of varying degrees of complication and reliability, we have finally settled on a foolproof method for communicating callouts from top camp to base camp: mobile phones. Cheap Austrian pay-as-you-go mobiles have sufficiently good reception on the plateau for sending SMS messages, and even occasionally for conversation.
For some years (including 2018) we have been using the "B-Free" mobile scheme provided by the A1 company. We get reception even inside the Stone Bridge bivvy. (In 2011 we tried using another provider which picked up the T-Mobile network, however the reception was not as good as B-Free.)
B-Free has an annual renewal of the SIM which gets you the phone number and connection (plus some credit). More credit comes in the form of a receipt with a printed code or a card with a scratch-off secret number.
This has to be done in less than 13 months otherwise it costs a more as you essentially have to start from scratch (~€10 for a new SIM with &euro5 of credit). The phone cannot be used in the last month, but renewal is cheaper than starting from scratch. "Renewal" is just a matter of buying another €20 credit.
The simplest way (which doesn't require understanding a number read out to you in German) is to dial *101# ("0 BALANCE" in the contacts list in the phone book). This doesn't actually make a call but results in you getting an SMS-like message containing the balance details. There's no charge for this.
If you need to buy more credits for a phone the simplest way is to buy a "B.Free" A1 top-up at the Post Office (closes 1200-1400 forlunch). We used to be able to get this form the supermarket, but no longer (2018). They'll give you a printed receipt with the code to key in. See below for how to use it.
Other options we've used were:
You should be given an "aufladecode", which may require scratching off a panel at lower right back of card) or just a long "till-receipt" strip with AUFLADEWERT: EUR 20.00 at the top.