Two Top Choices-12-36 or  More Telephones
Nortel was acquired by Avaya in 2009.

The best of the Legacy & IP best.
 

Feature Highlights

Voice Processing Platform

Multiple Party
Conference Calling

On-Board System
Backup

Wireless
with multiple Lines.

Avaya   IP Office-More Information
Up to 16 Interconnected Systems with 530 Telephones.
IP Office Demo Link  (15 Minute Overview)
http://www1.avaya.com/campaign/demo/ip-office/index.html  

Above: 5410 IP Office  Two Way Speaker Telephone

Compare Telephones: IP Office Station Comparisons

Case Study:  Typical IP Office with Cisco Networking

Productivity Platform: http://www.avaya.com/gcm/master-usa/en-us/home/index.htm?CMP=KNC-naggbrex&HBX_PK=www_avaya.com&HBX_OU=50

More about IP Office Legacy and Full VoIP  

Legacy Model
Merlin Magix Telephone Compatible

Multiple 
T-1 Circuit Connections.

 
Integrated ACD. & Networking.

IP Models:
Small office;
500 Platform;
406 V.2; or
412.

IP Office-T-1 Serial Connection . Extensive Multiple Site Networking.

Integrated With Automatic Call. Distribution

IP High End PC Integrated Voice Processing with ACD with Optional Wall Board Support.

Extensive CTI with Microsoft Platforms.

Memory Backup

Direct  Line Assignments

Excellent Wireless Option- 4 Line Handset.

Nortel IP Telephone

Overview: Flash demo: Nortel Platformew

 

Mid Range
Voice Processing.

Conference Bridge

Memory Backup.

PBX
Operations PBX

. Yes

 T-1 Capacity

System Backup

Key System Features

Wireless