In NI STS T2 tester - what is purpose of TTL0,TTL1,TTL 2,TTL3 in system block(P143)?

Hi ,

Iam unable to find community NI STS T2 tester.If community exists,please send the link to me ,else please forward below query to corresponding technical team related to NI STS T2 tester

Please explain the puropse of TTL0,TTL1,TTL 2,TTL3 pogo pins in system block(P143) in NI STS T2 tester.

Thanks & Regards,

Srinath.