Newton Developer Technical Information: Newton Programmer's Guide: 2.1 OS Addendum /

Chapter 9 - IrDA Communication Tool / IrDA Tool Option Reference

Discovery Option

In the discovery phase of a connection, the Newton unit probes and accumulates a list of other IrDA devices within beaming range. Each device is loosely identified by a service hints field (PDA/Computer/Printer/etc.) and a device nickname. The *kCMOIrDADiscoveryInformation option is used to specify which device to use and also how the Newton unit should appear to other devices that probe it.

You can also use this option after a connection has been made, to return information about the connection (the service hints of the discovered device, and its device address).

The following example shows the use of this option:

 local option := {

   label:  kCMOIrDADiscoveryInformation, // "irdi"
   type:   'option,
   opCode: opSetRequired,
   data: {
      arglist: [
         8,                // 8 probe slots
         kIrDASvcHintPDAPalmtop,// service hint
         kIrDASvcHintPrinter,// service hint mask
         0,                // devAddr of peer device
         1,                // use standard media busy check
      ],
      typelist: [
         'struct,
         'uLong, // fProbeSlots
         'uLong, // fMyServiceHints
         'uLong, // fPeerServiceHints
         'uLong, // fPeerDevAddr
         'uLong, // fMediaBusyCheck
      ], 
   },
};

The fields in the IrDA discovery option frame are described in Table 9-2.

Table 9-2 IrDA discovery option fields

Option field	Description
fProbeSlots	The number of "slots" used during probing. The valid choices are listed in Table 9-3. The default is kIrDA8ProbeSlot. This value relates to an IrDA collision-avoidance mechanism. It is recommended that you use the default setting unless you have a specific reason for changing it.
fMyServiceHints	The category of device that you wish to identify yourself as. The service hints are listed in Table 9-4. The default value is kIrDASvcHintPDAPalmtop.
fPeerServiceHints	A mask used to identify the categories of devices that you wish to connect to. You can OR together any combination of the values in Table 9-4 to construct this value. The default value is 0xFFFFFFFF (accept any device during discovery phase).
fPeerDevAddr	Read-only. Returns the address of the discovered device.
fMediaBusyCheck	To enable a 600ms. delay before discovery begins, specify true (default). To disable the delay, specify nil. It is highly recommended that you use the default setting. If you are using a sender/receiver model (like Newton beaming) then you may want to set this field to nil. But beware, for this invalidates IrDA compliancy with other IrDA devices.

Note that the service hints can be bit-OR'd together.

You can specify whatever you wish for the fMyServiceHints field, but the value kIrDASvcHintPDAPalmtop is always OR'd in by the IrDA tool.

Table 9-3 IrDA discovery option probe slots constants

Constant	Value
kIrDA1ProbeSlot	1
kIrDA6ProbeSlot	6
kIrDA8ProbeSlot	8
kIrDA12ProbeSlot	12

Table 9-4 IrDA discovery option service hint constants

Constant	Value
kIrDASvcHintPnPCompatible	0x00000001
kIrDASvcHintPDAPalmtop	0x00000002
kIrDASvcHintComputer	0x00000004
kIrDASvcHintPrinter	0x00000008
kIrDASvcHintModem	0x00000010
kIrDASvcHintFAX	0x00000020
kIrDASvcHintLanAccess	0x00000040
kIrDASvcHintTelephony	0x00000100
kIrDASvcHintFileServer	0x00000200

When used with the opcode opGetCurrent, the field fPeerServiceHints returns the service hints reported by the discovered device.

Note

Fields used during an endpoint Connect operation include fProbeSlots, fPeerServiceHints and fMediaBusyCheck. Fields used during an endpoint Listen operation include fMyServiceHints.

© Apple Computer, Inc.
26 APR 1997

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