Condition Value in a Field of Service Request

Question

my problem is this:
I want to insert a condition Value to a field(Long text) called "Recapito per il ricontatto".
Condition is this: I have another field called "Canale di Ricontatto" (Picklist) that have 4 choices: Telephone,*E-mail*,*Fax*,*P.E.C*
Now the condition value of "Recapito per il ricontatto"(Long Text) is this:
IF "Canale di Ricontatto" (Picklist) IS DIFFERENT Telephone(one choices of Picklist) THEN length least 7 characters
IF "Canale di Ricontatto" (Picklist) IS Telephone THEN no length least.
NOW in a FIELD "Recapito per il ricontatto"(Long text)field where I must insert the validation field,I put the Default value 'a' and i check the option Default value back and after i write in a validation field:
IIf([<plCanale_di_Ricontatto_ITAG>] < > LookupValue("OCC_CUST_LOV_SR_3", "Telefono"),Len([<ltRecapito_per_il_ricontatto_ITAG>])>6,Len([<ltRecapito_per_il_ricontatto_ITAG>])>=1)
But when i choose Telephone and i don't write nothing in a Long Text field("Recapito per il ricontatto") the allert goes out and when i choose another choice and i put for example 'aaaaaaaaaa'(10 characters) the allert goes out again. The allert goes out always.
Please HElp Me
Tank you,
Vale

Answer 1

I have resolved in this way:
Default value field (codice ASCII 255) and Ceck default back
And condition
[<plCanale_di_Contatto_ITAG>]<>LookupValue("OCC_CUST_LOV_SR_3", "Telefono")AND Len([<ltRecapito_per_il_ricontatto_ITAG>])>6 OR [<plCanale_di_Contatto_ITAG>]=LookupValue("OCC_CUST_LOV_SR_3", "Telefono")AND Len([<ltRecapito_per_il_ricontatto_ITAG>])>=1