Mercury Communications Ltd is close to a decision on how to replace its current billing system. The company is evaluating several options, from in-house development to buying in a package from GTE Corp. Mercury says that while it has only 500,000 subscribers at the moment, it is planning for 2m by 1995. Our current billing system is continually developing, and that serves us very well at the moment. But we’re looking on to 2m customers, and we really need to be looking to the next twenty or thirty years, it says. One of the options under consideration is a UKP25m software package from Stamford, Connecticut-based GTE. Others include upgrading the existing system – which seems unlikely, – and buying and modifying the GTE package, which is geared up to cope with US, rather than UK, billing systems and regulations. Mercury’s says that its wish list for the new system includes the ability to allow customers to choose the format for their bills, and the flexibility to speed up the introduction of new services. But Coming up with a system that fulfills 75% of our requirements, from the simple to the off-the-wall, would be great, it says.