Cables are like ribbing except on the row you cross the stitches. So if you knit the knit sts and p the purl stitches, you'll stay in pattern.
Is your example how the pattern actually reads or have you changed row 2? If it's the original pattern you would do exactly the same as row 1. - p1, (k2 p6, k2, p1) Only I suspect row 1 is the WS row; cables are generally made on knit sts and the only set of stitches in that repeat is the 6 and they're purled on R 1, so it probably isn't the RS.
sue- knitting heretic