December 04, 2000, 5:51 PM — With the industry buzz about voice/data convergence getting louder all the time, you
may soon find your phone system tied into your data network, with you centrally
controlling the whole thing from your PC.
We looked at AltiGen Communications' AltiServ, a Windows NT-based telephone and
voice mail system. AltiServ is a combination PBX, voice mail and messaging system
housed in a single NT server. With the addition of AltiWare IP, telephone calls can be
routed over an IP network to another AltiServ server.
While AltiServ Open Edition (OE) 2.1 has been on the market since late last year, we
now think it warrants closer examination because it blends PBX, PC and messaging
technologies into one system, and it costs anywhere from 30% to 75% less than
traditional phone systems with similar feature sets.
AltiServ is extremely simple to set up and requires little ongoing management. End
users can view and change their voice mail configurations using a Web browser.
Our tests show this product is well-suited for companies with several branch
offices, but some of the standing hardware limitations affect its overall scalability.
Currently, AltiServ is limited to 144 users per server because the system uses ISA
slots for the PBX/voice mail functionality and PCI slots for voice over IP.
We first tested AltiServ with voice traffic only. Our users reported the system was
easy to use, and their voices were clear and easily recognizable.
Next, using a packet generator we placed a moderate network load across our
pseudo-WAN link. Conversation quality degraded noticeably. Users said it sounded like
a terrible cellular phone connection.
We thought the problem was a traffic issue across the WAN link rather than a problem
with AltiServ, so we configured the routers to use Priority Queuing (packet
prioritization) for the voice-over-IP packets. Sure enough, voice quality returned to
its previous level.
In the version of AltiWare IP we tested, the bandwidth requirements for voice over
IP were surprisingly large compared to competitors' voice-over-IP products. AltiWare IP
requires 96K bytes per channel whereas other voice-over-IP products that support
compression require only 10K to 20K bytes per channel.
AltiGen is expected to release a new version of AltiWare IP this fall that will
Because users are accustomed to 24-7 telephone uptime, we also tested AltiServ's
power failure transfer feature, which lets designated telephone extensions remain open
in case of an interruption in electrical power.
We simulated a power outage in Office A. A UPS attached to the server -- which must
be purchased separately -- kicked in, and users noticed nothing.