1. IrLAP – Infrared Link Access Protocol By Mary Hsieh and Peggy Shen

2. Points that will be addressed The services that IrLAP provides The assumptions that are made about the environment when the protocol is executed The vocabulary of messages used to implement the protocol The encoding of the messages The procedures

3. Intro – Bit and Byte Ordering Datagram form Binary form Hex form Multiple Byte Form Note: Half Duplex

4. Intro (background info) – OSI and TCP/IP Models OSI Model Application Presentation Session Transport Network Data Link Physical TCP/IP Model Application Transport Internet Host-to-Network

5. Services – Definition Request Indication Response Confirm Upper Layer IrLAP Layer Request IndicationResponse Confirm Packets transferring

6. Data Link Services – (Continued) Discovery Services Discover what devices are ready or compatible Address Conflict Services Resolves device address conflict issues Unit Data Services Unreliable, connectionless way to send data, usually through broadcasting

7. Connection Oriented Service Connect Services Sniffing Services Data Services Status Services Reset Services Disconnect Services Example: IrLAP_service.request(Handle)

8. Environment and Operational Characteristics - Configurations Point to point, point to multipoint Half duplex Hidden nodes Narrow infrared cone (15 degree half angle) Synchronize transmission speed No collision detection

9. Data Link States and Modes Connection state Has a connection Contention state Waiting for a connection Modes NRM – Normal Response Mode NDM – Normal Disconnect Mode

10. Frame Structure To determine where the frame begins and ends To determine whether the frame is intended for that station To determine what actions to perform with the information received To detect the occurrence of transmission errors in received frames To acknowledge its receipt of frames to the transmitting station

11. Example of a Packet A normal packet

12. Elements of the IrLAP Frame Address Field – 8 bits ( least significant bit is the command/response identifier bit) Control Field U – unnumbered S - supervisory I - Information Information Field Must be a multiple of 8 bits

13. IrLAP Description of Procedures

14. Steps to Connect, Transfer, and Disconnect

15. Conclusion What may be useful for our project We can use the broadcast command to send out signal We know what the packets look like, so we can use the oscilloscope to see what they look like in analog form If we can ’ t use the IrDA port to transmit and receive signals through the skin, we could at least use it to transmit data that has been collected

16. Conclusion - Continued What would impede our project Half Duplex – if data cannot move in both directions at the same time, it may be difficult to send signals and get them back in a timely fashion Start/End Header – if we send a signal to the skin, the skin would not be able to generate a packet with headers that tells the IrDA port to get ready for data reception Bit Representation – it would be hard for us to control what is sent out in bits, etc.

17. Conclusion - Continued Therefore, we have concluded that we cannot use the IrDA port to do what we would like it to do. We would need a separate piece of hardware between the PDA and the laser diode to do the job.

18. Bibliography http://www.irda.org/standards/specifica tionsoldest.asp