ATIS and RAINWAT 

Automatic Transmitter Identification System (ATIS) is required for vessels making VHF transmissions whilst on the inland waterways of the Regional Arrangement Concerning the Radiotelephone Service on Inland Waterways (RAINWAT)signatory countries.

RAINWAT is the "Regional Arrangement Concerning the Radiotelephone Service on Inland Waterways" which, through the Basel Arrangement has introduced and Automatic Transmitter Identification System (ATIS) for vessels making VHF transmissions whilst on the inland waterways of the signatory countries:  Austria; Belgium; Bulgaria; Croatia; Czech Republic; France; Germany; Hungary; Luxemburg; Moldova; The Netherlands; Poland; Romania; Slovakia; Switzerland; Serbia & Montenegro.

The Regional Arrangement concerning the Radiotelephone Service on Inland Waterways [..]  is also valid for ships which are coming from states that are not members of the Regional Arrangement and sailing on inland waterways of the RAINWAT area. The usage of ATIS is mandatory for all such ships. Ship owners are responsible for equipping their ships with ATIS-capable equipment and a valid ATIS code.....
Extract taken from the RAINWAT website.

Where a VHF is required on the inland waterways of the signatory countries, this must be capable of ATIS transmissions, and have the feature activated. An ATIS number is required which is issued by Ofcom as a Notice of Variation to the Ship Radio Licence. This must be done manually, by Ofcom until such time as changes to the Ofcom licensing system are made to automate the process. The turn around time at Ofcom will increase in line with the number of requests received, however even if this is only a few days applicants must allow up to a month for Ofcom to supply details of the vessel to the Belgian regulator, BIPT, which oversees the ATIS database and for the BIPT database to reflect updates that are sent to it.

A copy of the Basel Arrangment should be carried on board. This can be downloaded from the RAINWAT web-site, however as the RYA has received reports of people having difficulty accessing the document, for your convenience the English Version from September 2007 has been downloaded and converted to pdf.

Ofcom has provided a comprehensive explaination of ATIS and RAINWAT on their web-site, which explains what ATIS is, how it works and the action you need to take prior to venturing onto the the inland waterways of the signatory countries including how to request the Notice of Variation to your Ship Radio Licence and thereby the ATIS number for your vessel.

It is important to note that under the the Notice to Variation of the Ship Radio Licence, ATIS shall not be used within 14 nautical miles of the low waterline around the coast of the UK, the Isle of Man and the Channel Islands.

The use of DSC (VHF Ch. 70) is in most countries restricted to coastal waters and DSC transmissions should not be made when navigating the inland waterways.

Not all VHF sets are capable of ATIS transmissions; you may need to contact your manufacturer for advice.