 of sophisticated liquid crystal displays has spawned a new generation of intelligent front panels which can be The future of modem applications depends on a variety of tariffing, used to programme both local and remotely connected units without technological, business and political factors operating at both na- the need to attach a separate programming terminal via a console tional and international level and the extent to which any one of port. This is a boon in the synchronous environment allowing in situ them can dominate. reprogramming and diagnostics. The short haul modem suffers the least from pressures like public network digitisation and tariffing. Technologically it is charac- terised by a level of miniaturisation and cost reduction that further 39.5.2.12 Diagnostics development would be hard pressed to improve, where medium speed, limited distance interoffice and on premise intersite connec- Once proprietary but now conforming increasingly to the CCITT tivity is required. Commercially it is firmly established as a com- V.54 standard, diagnostic tests typically include the local analogue modity product and is becoming an integrated part of structured and digital loop, and remote digital loop often with a test pattern cabling systems. The only real threat to its existence is the demand generator and decoder to simplify both the initial installation and on bandwidth to the desktop of new computing and workstation subsequent fault isolation. applications. By contrast, the long haul dial up and leased line modem suffers more, reflected by the effort put into its technological advancement. 39.5.2.13 Timing The last few years have seen an upsurge in dial up applications, triggered by the introduction of 2 wire V.32 technology coupled To allow for both synchronous and asynchronous operation, with echo cancellation, trellis encoding, error correction and data modems must be capable of being driven by a range of clock compression techniques. sources. Satisfying a user need for faster, less error prone communicat