When DX Spectrum is integrated with CA UIM not all devices are visible into DX Spectrum.
Any UIM or DX Spectrum Version
With DX Spectrum 9.4.0 release and above, DX Spectrum will only pull and model UIM entities of type “Host”. When integration with UIM is enabled in DX Spectrum, the table from which data is returned is the CM_COMPUTER_SYSTEM table.
Each row in this table has a field called “dedicated”- which specifies the type of entity that the row represents. Only the rows with “dedicated” field as “Host” will be reported to DX Spectrum.
For verifying, the following query can be executed on the SQL server of the DX UIM
select * from CM_COMPUTER_SYSTEM where dedicated = 'host'
If the entry is not "host" then it will not be populated in DX Spectrum.