Wireless LAN becomes popular in offices. In fact, the office where a network is operated only by wireless LAN has appeared. Demands are increasing for layout independent network where PCs, printers, and multi-function printers (MFPs) are connected without cables. An optional board featuring this technology adds speed and high security to document management including printing and “scan-to-Email” in a wireless environment. Another advantage of this technology is a stable connection that is not easily affected by fluctuations in the wireless environment, under the rapid increase in a wireless LAN node in recent years.
This technology is carefully implemented to ensure stable, high-speed wireless LAN communications. The antennas are specifically optimized for desktop and floor-standing printers/MFPs. We integrated features needed for this new technology into the control LSI (with built-in CPU and memory) with embedded software.
Figure 1: Option board for desktop devices and installation
Figure 2: Option board for floor-standing devices and installation
Ricoh developed the following core modules for the technologies conforming to IEEE802.11 wireless LAN standards:
Figure 3: Modules developed by Ricoh
Ricoh developed the control software for the hardware modules in this sublayer and lower-level layers. The software receives commands from higher-level layers (such as device drivers) and establishes communications with the destination terminal using protocols conforming to the standards. The development team thoroughly verified interconnectivity with a variety of terminals, and carefully designed the algorithm to improve connectivity.
The LSI is an SoC (System on Chip) device integrating CPU, memory, and AD/DA converters. It is a key device that provides data framing, time management, encryption, modulation/demodulation, and interfaces for MFPs and laser printers. Supported encryption schemes are WEP (ARC4), TKIP (ARC4), and CCMP (AES), and supported modulation/demodulation schemes are DBPSK, DQPSK, BPSK, QPSK, 16QAM, and 64QAM for primary modulation and DSSS/CCK and OFDM for secondary modulation. The architecture is optimized for MFPs and laser printers; rich functions and performance are integrated into one chip.
This circuit supports channels of the 2.4 GHz band and the 5 GHz band. Support for the 5 GHz band allows users to enjoy high-speed communications in an environment where interference waves are marginal. The circuit is approved under local regulations in many countries and regions – Japan, USA, Canada, Europe, China, and Taiwan. While the board is common to all countries and regions, it operates in accordance with radio wave restrictions of the shipping destinations.