After being referred by a HH I had a phone interview with an employee in a similar position I was interviewing for. This was a very kind guy and he explained me what the position was. It did not match my background; but is was a nice conversation. He tested me a bit on technical questions for Linux/Unix, Perl and SQL. At the end he also asked two brain teasers. Afterwards he wanted me to do some online tests: again Linux/unix, Perl and SQL. The tests weren't hard; with average SQL knowledge you should be able to pass it. As I did not any Perl or Linux experience I can really judge about these tests, but most of the questions did not look that hard (notation / commands).