The mains differences are as follows:
*The T19PN has one SIP account. The T21PN has two (it also has easy to use line keys on the side of the display).
*The T21PN has superior HD audio components, the T19PN doesn’t.
*The T21PN has LDAP directory support, the T19PN doesn’t.
Apart from that, and the colour of the LCD support, everything else is the same.
Yealink T19PN datasheet can be found here
Yealink T21PN datasheet can be found here
Should you have any further queries give the Sales Team a call on 01484 840048 or send an email to firstname.lastname@example.org
The ProVu Team