How to write key value using PowerShell?

Hi~.

I try to control MS-DOS program. 

The program name is CARI-6M. 

You can download http://www.faa.gov/data_research/research/med_humanfacs/aeromedical/radiobiology/cari6m/ . 

The CARI-6M has text GUI environment. 

I don't know to write key "1" using Write-Output cmdlet.

I want to input keys instead of human's typing. 

Could you advise some solution? 

Please, help me~~~

----My PowerShell Script--------------

cd c:\cari6mex

dir

.\cari-6m.exe

Write-Output "1"

--------------------------------------