I need to unset & reset TERM environment variable from .login

[Richard Sutton]

I want to start using a new version of telnet to connect my PC to a Sun
Sparc Station I running SunOS 4.0.3c . This version of telnet automatically
sets TERM to vt102. A number of software packages we have don't recognize
vt102. 

Rather than manually doing a unsetenv TERM followed by a setenv TERM = vt100,
could anyone tell me how to have .login detect that TERM is vt102, then 
reset TERM to vt100? Please mention which FM if the answer is RTFM.

Thanks in Advance,

Rich