The CellStack Capella MCU is a video conferencing device that provides high quality audio and video for conferences of up to 8 participants. It uses ATM networking and distributes audio and video streams to minimize bandwidth usage. Key features include automatic audio switching between conference speakers based on signal levels, chairman controls for larger conferences, and support for distributed configurations to reduce costs.

1. Product Data Sheet
CellStack
Capella MCU
MultiPoint Conference Unit
• High quality, low latency video and
audio conferencing
• Full stereo audio for ‘Natural’ sound
• Scaleable and distributed – up to 8
parties per MCU
• On demand, fast switching
• World’s only ‘cell based’ award
winning MCU
For Video Conferences A primary MCU controls the overall
conference – including the broadcast
Audio Switching
Large and Small of audio and video. It can also be Each CellStack MCU can receive up
supported by secondary MCUs to eight stereo audio streams and
responsible for distributed employ real-time signal level analysis
configurations including localised to determine who should be the
The CellStack Capella MCU is audio level analysis. current conference speaker. Whilst
a video conferencing optionally allowing a mix of audio
The Benefits of CellStack MCU channels to be redistributed to
Multi-point Control Unit. conference participants, CellStack
It provides for support of a CellStack Capella MCU is based MCU will monitor the signal levels of
distributed hierarchy where around standard ATM switching all incoming channels and
(UNI 3.0/3.1), digital regeneration of continuously assess whether the
CellStack Capella Video codecs audio and video cell streams, and conference speaker should change.
can be connected in a variety the use of ATM’s inherent multicast
of configurations according to capabilities. It ensures minimal Boasting in-built controls to avoid
switching times between speakers over-rapid switching and prevention
the user’s needs; enabling and reduced bandwidth distributed of false triggers due to rustling
costs to be kept to a minimum throughout the ATM network. With papers or doors closing, this
for small conferences (up to 8 significantly lower costs of ownership functionality is ideal for small to
users). However, it also and each unit able to function in a medium conference situations.
primary or secondary role, CellStack
accommodates larger MCU heralds a new era in high Chairman Control
conferences, regardless quality multi-point conferencing.
In larger conferences or where
of whether users are located Conference Management chairman control is specifically
locally, or separated by required, CS Desktop in conjunction
thousands of miles. Overall control of a conference is with MCU/CellStack Video control
through a user-friendly graphical messaging, provides the chairman
application – CS Desktop, which with a clear indication of who is
provides a management interface participating and who is requesting
enabling the conference chairman to the “floor”. Simple use of the mouse
determine which CellStack locations driven graphical interface enables
are included in a particular the chairman to allocate control
conference session. It can also be accordingly.
decided whether the conference is to
be controlled by a chairman or by Lecture Control
automatic audio level analysis – an
MCU function. Operation as for ‘audio switching’,
but with the outbound channel fixed
on the main lecturer/speaker.

2. Technical Specifications
ATM UNI: Auxiliary Data / Console
ATM interface modules include: RS232 interface configurable up
to 19,200bps,
UNI v3.0/3.1 155 Mbit/sec OC-3/STM-1 8 data bits, no parity
SONET/SDH Singlemode fiber Connector: 9 Pin Male ‘D’ type
(9/125 µM)
16dB = Typical range: ~ 24km Operating Characteristics:
26dB = Typical range: ~ 40km Power:100/240 Vac, 50/60Hz
auto ranging
UNI v3.0/3.1 155 Mbit/sec OC- Power Tolerances: 88-264 Vac,
3/STM-1 SONET/SDH Multimode 47-63Hz
62.5/125uM fiber (& 50/125uM) Max Power Consumption: 13W
Typical range: ~ 2km Operating Temperature: 0 – 40
degrees C
UNI v3.0/3.1 155Mbit/sec Operating Humidity: 10-90% non-
Category 5 UTP condensing
Typical range: ~ 100m
Ordering Information
Dimensions
AAL5 adaptation layer supported for Tabletop CellStack Capella MCU including
all Audio, Video, Data and control / Width: 438mm 155Mbps OC-3 ATM UNI module:
command channel input and output Height: 44.5mm (52mm incl feet)
data. UBR and VBR operation Depth: 325mm CS-CAP/M/001: ATM Interface Module
– Multimode, SC connector
supported. Weight: 4 kg
CS-CAP/M/002-16dB: ATM Interface Module
– Singlemode, SC connector
Switched Virtual Circuits Rackmount
CS-CAP/M/002-26dB: ATM Interface Module
CellStack supports ATM Forum UNI Width: Standard 19" rack fitting
– Singlemode, SC connector
v3.0 and v3.1 signaling Height: 44.5mm (52mm incl feet) CS-CAP/M/003: ATM Interface Module
Depth: 325mm – Category 5 UTP RJ45 connector
,
Weight: 4 kg
CellStack Systems Inc CellStack Systems Ltd
Suite 245 Brookmount Court
5068 W. Plano Parkway Kirkwood Road
Plano, Texas 75093 Cambridge CB4 2QH
USA UK
Tel: + (972) 713-8999 Tel: +44 (0) 1223 509300 e-mail: info@cellstack.com
Fax: + (972) 713-9597 Fax: +44 (0) 1223 509310 http://www.cellstack.com
Toll Free: (888) 236-5638