The horizontal market is characterised by the use of standard applications. The wireless network offers a standard protocol interface, for example TCP/IP. This means that users can buy off-the-shelf software, plug in their wireless modems and go. Because the network offers a standard interface, the software does not need to be specifically developed for the wireless network. This opens up a much broader market, as users are no longer constrained by the availability of specialist applications, so e-mail, database access, two-way paging and web browsing are all easily available.
In this picture, point-of-sales is shown as being a part of the horizontal market. In actuality point-of-sale lies in a a grey area, as it relies on a series of standard and non-standard protocols.