Chapter 8: Telephone Planning and Ordering Planning and Installation Guide
ShoreTel 11.1 103
8.3.7 Multi-line Phones
ShoreTel offers extension monitoring from an IP phone. With this feature, an
administrative assistant or workgroup supervisor can monitor up to five system extensions.
The extension monitor feature can be enabled for ShoreTel IP phones from the User edit
pages of ShoreWare Director. For more information, see the ShoreTel Administration Guide.
Both analog and IP phones can be included in a ShoreTel system as remote phones. Analog
phones require use of the Extension Assignment, while IP phones are supported by setting
an IP address range through ShoreWare Director.
8.4 Fax Machines and Modems
The ShoreTel system supports fax machines and modems in the United States and Canada
(and not elsewhere).
Fax and modem calls are more sensitive to network problems than voice conversations.
The human ear does not notice a lost packet during a voice conversation, but when a
packet is lost during a fax transmission the line may be dropped. During a modem call, a
lost packet can cause a retransmission. In the worst case, fax machines and modems will
not establish a connection or may drop the call altogether. In general, fax and modem calls
work across a local area network, but work on wide area networks only when there is
virtually no packet loss and little jitter.
The ShoreTel system automatically detects both fax and modem tones, and boosts the voice
encoding to a higher value to increase throughput. (G.711 at 64 Kbps is recommended.) It
also stops the nonlinear processing of the echo canceller and fixes the size of the jitter
buffer to a preset level. In addition, for modems, the echo canceller is frozen or stopped,
since the modems use their own network echo cancellers.
8.4.1 Fax Machines
Fax machines require a high-quality IP network for proper operation.
The ShoreTel system supports distinctive ringing for inbound calls: calls from external
parties have the classic single ring, whereas calls from internal parties have a distinctive
double ring. Some fax machines detect the ringing pattern before answering and might not
answer internal calls because of the distinctive ring pattern. In particular, you must turn off
the “Intelligent Ring Mode” on some Hewlett-Packard fax machines to receive calls from
The ShoreTel system supports “moderate-use” modem applications on the system. This is
generally considered to be modem calls up to 28.8 Kbps that do not last longer than 15
minutes. If your application demands greater performance, you should bypass the ShoreTel
system or move your modem application to a pure IP-based solution.
The expected modem performance in different configurations is as follows:
Analog connection speeds will not exceed 33.6 Kbps and could be lower. External
factors, including poor-quality trunk lines, ISP limitations, and multiple analog-to-
digital conversions in the network, can have a significant impact on connection