There is also Sri Monkel who operate the route mostly with a new fleet of 14 Double decker VIP buses,they leave Pattaya from 3rd road about 300 yds on the left from the traffic lights in Pattaya Klang heading for Pattaya Nua.The route no is 589 ,the route is Pattaya -Ubon,50% go via Buriram,50% go via Surin.So make sure you get the right one.I've used it many times to get here in Nong Ki,the fare was 340 baht last month,the one I tend to catch leaves Pattaya at 07-30 gets to Nong Ki 15-30,it stops in Korat for 1 hour.I don't know thw timetable from Buriram but I have seen it on its way from Buriram to Korat passing Makro at around 10-30.There is also a Pattaya -Mukdahan bus <bright yellow> which goes into Buriram ,this leaves Pattaya from the Bus station on Pattaya Nua.