CS 1000; and therefore, Device Adapter identifies each UNIStim station by a hardware port ID or Terminal Number (TN). In CS 1000, all TNs must be unique. No two devices can share a TN, although, they can share MADN numbers, feature key definitions, and so on.
If you want to allow a user to use two or more Device Adapter UNIStim endpoints by using Sequential Registration, you must set the Max. Simultaneous Devices MDA configuration field value to 1. If you set the Max. Simultaneous Devices value to more than one, redundancy and call processing problems occur.
The endpoints may fail over to a geographic redundancy cluster and the Device Adapter cluster cannot recognize that the other endpoint exists.
Device Adapter does not correctly handle call-related messages. Hence, the call processing fails.
As a result, if you want to have a 1140 and a 2050 share a user extension and station definition, then only one of these endpoints can be active. Hence, the Max. Simultaneous Devices value must be set to 1. Any other value is not supported if you want to configure Sequential Registration and allow two or more Device Adapter UNIStim endpoints.
Therefore, whenever a 1140 UNIStim station is the active station for a user, the user receives the CS 1000 user experience for the 1140 UNIStim station, if:
The user station is configured as 1140.
The user is logged in and registered with a 1140 UNIStim station.
In addition to the 1140, if the user also has a 2050 soft client, the user can log in by using the same user identity. But, because the node and TN are the same, Device Adapter cannot register both the endpoints concurrently. If Max. Simultaneous Devices is set to 1, the Session Manager that receives the SIP REGISTER message terminates the registration of the 1140 endpoint and registers the 2050 soft client.
Because the 2050 and 1140 have the same basic layout, there is no difference in the base feature handling. However, if the 1140 has expansion modules, the station definition includes these modules. If 2050 does not have the modules, the extra keys are lost when the user uses the 2050.
Note that allowing the 2050 to register by terminating the 1140 registration was inherently unstable in releases prior to Device Adapter Release 8.1. From the messages received, Device Adapter is aware that Session Manager has ended the UNIStim set registration. Device Adapter prevents re-registration without deliberate user operations.
However, if the endpoint loses network service, the endpoint restarts and tries to register to a new server. The new server might be in a geographic redundancy cluster; and hence, does not have access to the information in the prior device.
To resolve this problem, since Release 8.1, Device Adapter stores the registration termination status within the endpoint. Thereby, preventing the endpoint from registering with Session Manager until the user chooses to do so. Hence, the endpoint does not try to re-register automatically.
