10 caractères Num (0-9) et 4 blancs
If len(replace(Me.Tbx_TelMob.Value)," ")=10 and len(replace(replace(replace(replace(replace(replace(replace(replace( (replace(replace(Me.Tbx_TelMob.Value,"0",""),"1",""),"2",""),"3",""),"4",""),"5",""),"6",""),"7",""),"8",""),"9",""))=4 Then