2 days ago
- IrDA originated from HP's RedEye protocol for wireless calculator printing, evolving into HP SIR and later becoming the industry-standard Infrared Data Association (IrDA) protocol in 1993.
- IrDA's physical layer evolved from SIR (115 kbps) to MIR (1 Mbps), FIR (4 Mbps), VFIR (16 Mbps), and experimental UFIR (96 Mbps) and GigaIR (1 Gbps), but adoption waned with the rise of Bluetooth and Wi-Fi.
- The IrDA protocol stack includes IrLAP for discovery and link access, IrLMP for multiplexing and service discovery via LM-IAS, and TinyTP for flow control and segmentation, enabling applications like IrCOMM (serial port emulation), IrJetSend (printing), and OBEX (file transfer and PIM synchronization).
- OBEX, operating over TinyTP, supported file sharing and business card exchange via verbs like GET, PUT, and SETPATH, similar to HTTP/FTP, and was widely used for 'squirting' files between devices.
- IrDA declined due to convenience advantages of Bluetooth/Wi-Fi, integration costs, and limitations like line-of-sight requirements and poor sunlight performance, though it persists in niche embedded applications for low cost and RF-free security.
- IrLAN attempted to implement IP over IrDA with multi-client access point mode, but lacked widespread support due to IrLAP's point-to-point limitations and competing protocols like PPP over IrCOMM.