In the auto-discovery access mode the DS Manager can detect and access all local Device Servers, even those whose IP-address is "unreachable" (incompatible with the network settings of the PC, conflicts with the same IP-address set on another Ethernet device, etc.).
Device Servers with unreachable IP-address are accessed using broadcast communications (broadcasts do not depend on the IP-address of the device in any way)*. The downside of this method is that broadcasts cannot pass through the routers so only local Device Servers can be accessed this way (hence, the method is only used in the auto-discovery mode).
 | Devices with unreachable IP-address are displayed in the device list with their status icon "grayed" (see sample icon on the left). For complete list of all icons please turn to DS status icons. |
Note, that conditions that cause the IP-address of the DS to appear to be unreachable may be temporary. See troubleshooting (auto-discovery mode) for details.
Programmer's info:
The DS Manager determines which Device Servers can be accessed using "normal" IP-addressing (and which- cannot) by performing the following procedure:
| • | When the Refresh button is pressed (in the auto-discovery mode) the DS Manager sends out a broadcast Echo (X) command. This command reaches all local Device Servers, even the ones with unreachable IP-address. Devices shown in the device list are those that have replied to the broadcast. |
| • | Next, the DS Manager sends out non-broadcast Echo (X) commands directly addressing each DS in the device list (so as many commands are sent as there are devices detected in the previous step). If there is a reply to a command addressing a particular DS then the DS Manager considers the IP-address of this device to be reachable. Otherwise, the DS Manager marks this DS as having an unreachable IP-address and accesses it using broadcasts. |
The ability to access and program Device Servers using broadcast communications is delivered through the use of the Select In Broadcast Mode (W) command. You can also read about how this works in the following topic: Broadcast out-of-band commands.
* Broadcast programming is not supported by Device Servers with the older firmware (earlier than V3.xx). Such Devices must be assigned a reachable IP-address before they can be accessed by the DS Manager.