Specifications
Planning Applications and Services
Planning and Installation Guide 11 – 9
ShoreTel 6.1 Fax Server Requirements
• Sufficient ports on ShoreGear-120/24 voice switches.
— One telephone port for each outbound fax port.
— One trunk port for each user’s inbound fax port.
• Sufficient ShoreWare User Licenses.
• Sufficient DID trunks to support both fax and voice DID for all users.
Network Requirements
The network requirements for fax over IP are more stringent than for voice over IP. For
voice communications, a 1% packet loss has negligible impact on voice quality.
However, a 1% packet loss for fax communications means a loss of approximately 3
lines per fax page. ShoreTel recommends that packet loss not exceed 0.1% across the
LAN and WAN when using fax servers with the ShoreTel 6.1 system.
Fax communications are also impacted by voice compression. Since fax machine
typically require 19.2 Kbps, ShoreTel recommends that you use G.711 voice encoding
for fax calls. For more information on fax requirements, see “Fax Machines and
Modems” on page 8-3.
Note that the fax redirect feature will not work with calls that come in on SIP trunks.
Fax Server Integration Details
Instead of requiring users to have two separate DID numbers (one for voice and one for
fax) a single DID line can handle voice calls and inbound/outbound faxing.
A user's extension (which can be 3, 4, or 5 digits) is sent to a fax server via in-band
Dual Tone Multi Frequency (DTMF) digits. The fax server uses this information to
create a mapping between the user's extension and his or her email address.
Once configured, incoming fax calls are received at the user's phone extension. The fax
server listens for the fax tone, takes over the call, and forwards the fax to the associated
email address (assuming the fax redirect radio button has been selected in Director).
When the fax transmission is complete, the loop current is automatically turned off to
terminate the fax call.
Figure 11-2 Fax server integration call flow
1. Fax call
2. User or voice mail
answers Fax call
3. Call is redirected to
fax redirect extension
4. Fax server answers
5. DTMF of
dialed number
invokes Fax
Mailbox