Type the following commands at the Windows Command Line:
Watch the Video here

Telnet
set localecho
set logfile Telnet.txt
Open pmta.zululabs.com 25  (you can Ports try 465 or 587 as well)
EHLO pmta.zululabs.com
AUTH LOGIN
dXNlcm5hbWU=                    (this is your Account SMTP Username encoded with base 64 encoded)
cGFzc3dvcmQ=                     (this is your Account SMTP Password encoded with base 64 encoded)
MAIL FROM:usereyou@domain.com
RCPT TO:abuse@zululabs.com NOTIFY=success,failure
DATA

Subject: Sending an email using telnet

[Press Enter again ]               (A blank line is needed between the Subject: field and the message body)

Hello,

Cheers

.                                                 <-- (Don't forget the period to close and send the message)

quit

********
There are many Base64 encoders available or you can use a perl command such as 
perl -MMIME::Base64 -e 'print encode_base64("username");'



Telnet OutPut

C:\Windows\System32> telnet
Microsoft Telnet> set localecho
Microsoft Telnet> set logfile c:\TelnetTest.txt
Microsoft Telnet> OPEN pmta.zululabs.com 25
220 pmta.zululabs.com Microsoft ESMTP MAIL Service ready at Fri, 5 Aug 2016 16:24:41 -0700
EHLO contoso.com
250-pmta.zululabs.com Hello [202.43.3.143]
250-SIZE 37748736
250-PIPELINING
250-DSN
250-ENHANCEDSTATUSCODES
250-STARTTLS
250-X-ANONYMOUSTLS
250-AUTH LOGIN
250-dXNlcm5hbWU=
250-cGFzc3dvcmQ=
250-BINARYMIME
250-CHUNKING
250 XRDST
MAIL FROM:usereyou@domain.com
250 2.1.0 Sender OK
RCPT TO:abuse@zululabs.com NOTIFY=success,failure
250 2.1.5 Recipient OK
DATA
354 Start mail input; end with .
Subject: test
 
This is a test message.
.
250 2.6.0 <c89b4fcc-3ad1-4758-a1ab-1e820065d622@edm.zululabs.com> [InternalId=5111011082268, Hostname=pmta.zululabs.com Queued mail for delivery
QUIT
221 2.0.0 Service closing transmission channel