Automatic Signon/Telnet: How can the 5250 client differentiate between V5R1 and Pre-V5R1 Releases at signon time?

The following summarizes the cases when to use DES7 or SHA1 Password
Encryption before coming to my question:

If the remote system is running OS/400, you should set the encryption based
on the release level and the system value for password level (QPWDLVL) on
the remote system as follow:

    .If OS/400 on the remote system is at release level V4R5 or earlier,
specify *DES7. 

    .If OS/400 on the remote system is at release level V5R1 or later, and
QPWDLVL has a value of '0' or '1', specify *DES7. 

    .If OS/400 on the remote system is at release level V5R1 or later and
QPWDLVL has a value of '2' or '3', specify *SHA1. 

 

If the encryption algorithm used does not match what is expected by the
remote system, the automatic sign-on will fail and the user is presented
with a sign-on display on the target system, or a failure message on the
source system, depending on the configuration of the target system. 

 

The Question is: How the 5250 client can differentiate between V5R1/Pre-V5R1
Releases, Password Levels '0' or '1' /  '2' or '3' in the protocol when
negotiating the AS400 using TCP/IP Telnet connection? Which indicator in the
protocol says when to use DES7 or SHA1 Password Encryption?

 

Thanks

N.Khoury