Wavelink - Products - Polycom Spectralink Wi-Fi

On this page we address a comprehensive range of questions, issues, and concerns regarding SpectraLink Wi-Fi Products. Please select a subsection beneath the product you are inquiring about and you will be taken to a list of appropriate questions and answers.

› SpectraLink Docking Stations
› Network and Wireless LAN Considerations
› Product Specifications
› Push-to-Talk (PTT) Feature of the SpectraLink i640 Wireless Telephone
› Security
› SpectraLink Wi-Fi Voice Priority (SVP)
› Standards Compliance

SpectraLink Docking Stations

What is a SpectraLink Docking Station and how is it used?

The SpectraLink Wi-Fi Docking Station serves as full-featured wireless desktop telephone set when docking a SpectraLink Wi-Fi Wireless Telephone. The SpectraLink Docking Station's large alphanumeric display and keypad, feature access keys, and integrated speakerphone provide the advanced features and capabilities of a high-end business telephone deskset with the additional advantage of a mobile handset. It is designed to meet the needs of employees who want a typical deskset but also want to carry a full-featured telephone with them when they are away from their desks.

Is there a seamless handoff between the docking station and handset or do you put the call on hold and recall it?

Calls will stay active when switching from the handset to the docking station or vice-versa. For example, a manager may be on an call using the docking station and want to ask one of their employees the status of a particular project. The manager could simply pick up the wireless handset and walk over to the employee to resolve the question on the spot.

Which SpectraLink Wi-Fi platforms support the docking stations?

The SpectraLink Docking Stations require the use of the SpectraLink Telephony Gateway, therefore, they are only supported on integrations to a legacy PABX (i.e, not currently supported on IP PABX implementations).

Is the speakerphone on the SpectraLink Docking Station full duplex?

The speakerphone for the SpectraLink s340 and s640 Docking Stations is a half-duplex speakerphone.

Will the SpectraLink Docking Station charge my handset or do I need a separate charging stand?

The wireless handset cradle on the docking station acts as a charging stand as well as providing connectivity from the wireless telephone to the docking station. Wireless telephones can reach a full charge in approximately 1.5 hours.

Important info regarding charging using the dual charging stands: The scenario is, both the spare battery and the handsets are not charged at the same time, but rather which ever was inserted first (either the spare battery or the handset). This means that if a spare battery was inserted first into the dual charger stand and then the handset - the handset will not be charged once it is inserted, but once the spare battery is fully charged, then the handset begins to charge.

Network and Wireless LAN Considerations

What are the network requirements to deploy SpectraLink wireless telephones?

A comprehensive discussion of the network requirements are provided in the deploying SpectraLink wireless telephones: Click here.

How much bandwidth does a SpectraLink Wireless Telephone use?

When not in an active call, a SpectraLink Wireless Telephone uses the same amount of bandwidth as any idle Wi-Fi client device. When in a telephone call, the bandwidth utilized varies depending on the transmission data rate and the type of voice encoding used. For example, a call using standard 64 kb/s voice encoding (G.711) utilizes about 4.5% of the AP bandwidth at 11 Mb/s and about 12% at 2 Mb/s. Note that about 30% of the AP bandwidth is needed for re-sending packets and dynamic channel allocation, so that only 70% of the AP bandwidth is available for SpectraLink wireless telephones and other client devices.

Is IP multicast required for the SpectraLink wireless telephones?

IP multicast addresses are used by the SpectraLink wireless telephones for most interfaces and for the SpectraLink i640 PTT feature. This requires that multicasting be enabled on the subnet used for the SpectraLink wireless telephones, SpectraLink SVP Server, and SpectraLink Telephony Gateways. Routers are typically configured with filters to prevent multicast traffic from flowing outside of specific domains. The wireless LAN can be placed on a separate VLAN or subnet to reduce the effects of broadcast and multicast traffic from devices in other network segments.

How many SpectraLink Wireless Telephone calls can an access point support?

The number of simultaneous calls supported by an access point depends on the data rate, the voice encoding algorithm, protocol overhead, and performance of a specific manufacturer's AP. In general, approximately twelve simultaneous calls are possible if all twelve are operating at 11 Mb/s. Fewer calls are supported if the SpectraLink wireless telephones need to drop to a lower data rate. The network administrator can set the maximum number of simultaneous voice calls over a single access point, thus preserving bandwidth for data applications.

How are the SpectraLink Wireless Telephones managed on the network?

SpectraLink Wi-Fi wireless telephones are as simple to administer and maintain as any other client on a wireless network. Each Wireless Telephone requires an IP address, which can be statically assigned or provided by a DHCP server. SpectraLink wireless telephones also include a TFTP client, allowing automatic software updates from a local TFTP server.

Can an active call be maintained while roaming between LAN subnets?

Maintaining an active call requires tunneling or some other mechanism to preserve the IP address of the handset as it changes subnets. SVP timing may require a SpectraLink Wi-Fi SVP Server on the same subnet as the APs as well.

What is the range of the SpectraLink Wireless Telephones?

The range of the radio in a SpectraLink Wi-Fi Wireless Telephone handset varies according to a number of factors, including internal wall construction, obstructions, AP output power, and RF transmission type. Also, range varies by AP vendor. Considering all of these variables, the range in a given customer environment can vary significantly. However, in laboratory tests the typical indoor range between a SpectraLink Wi-Fi Wireless Telephone and AP is approximately 45 to 60 metres.

Does adding SpectraLink Wireless Telephones to a wireless LAN require more access points?

Like any client devices, adding SpectraLink wireless telephones to a wireless LAN increases the bandwidth requirement because of the increase in traffic load. A lightly loaded wireless LAN may not require additional APs. However, on a moderately to heavily loaded wireless LAN or where additional coverage area is needed, additional APs may need to be installed.

Product Specifications

What are SpectraLink Wi-Fi Wireless Telephones?

SpectraLink Wi-Fi wireless telephones are mobile handsets for enterprise use, which provide high quality voice communications throughout the workplace using voice over IP (VoIP) technology. SpectraLink Wi-Fi wireless telephones operate over a Wi-Fi wireless LAN, giving users the freedom to roam throughout the workplace while providing all the features and functionality of a traditional or IP-based telephone switch.

Which telephone systems do the SpectraLink wireless telephones support?

SpectraLink wireless telephones are designed to integrate with both traditional PABX telephone systems and IP-based telephony servers, allowing a simple migration path for enterprises that change their telephone switching architecture. For applications using traditional enterprise PABX systems, the SpectraLink Wi-Fi Telephony Gateway connects to the host telephone switch using digital or analogue line interfaces. The SpectraLink Wi-Fi Telephony Gateway provides the IP conversion and packetization of the voice and control signals from the PABX. The SpectraLink Wi-Fi wireless telephones also support standard and proprietary IP protocols for end-to-end IP telephony applications. The handsets serve as IP end-points, eliminating the need for a separate VoIP gateway. A complete list of supported telephone systems is found on our website.

How do SpectraLink Wi-Fi Wireless Telephones compare to the Link Wireless Telephone System?

From the end user's perspective, SpectraLink wireless telephones provide the same functionality and quality as the Link Wireless Telephone SystemTM (Link WTS). The choice between the two SpectraLink solutions is based on the customer's infrastructure and management preferences. SpectraLink wireless telephones allow telecom and IT managers to simplify their wireless infrastructure by combining voice and data applications on the same network. Customers are able to leverage their investment in Wi-Fi wireless LANs and preserve their investment in traditional or IP PABX technology. Because Wi-Fi is an international standard for wireless LANs, SpectraLink wireless telephones can be the choice for wireless telephony throughout the global enterprise. The Link WTS remains the economical choice for customers who need to implement a voice-only wireless solution.

What is the SpectraLink Wi-Fi Telephony Gateway?

The SpectraLink Wi-Fi Telephony Gateway allows SpectraLink Wireless Telephones to interface to analogue or digital station ports on a telephone switch. It converts individual voice circuits on the PABX to IP packets on the LAN. Each SpectraLink Telephony Gateway supports either 16 analogue or digital ports (refer to the Telephone Switch Interface Matrix for details on the digitally supported switches). Up to 40 SpectraLink Telephony Gateways can be combined in a network to support a maximum of 640 SpectraLink wireless telephones.

What is the SpectraLink SVP Server?

The SpectraLink SVP Server is a dedicated network appliance that works with the wireless LAN access points to guarantee Quality of Service (QoS) by utilizing SpectraLink Voice Priority (SVP). The SpetraLink SVP Server controls timing of packet transmission and inserts the proper header information into voice packets to trigger SVP prioritization in the access points. All call setup and audio packets are routed through the SpectraLink SVP Server.

Is the SpectraLink SVP Server a required component of the SpectraLink Wi-Fi System?

Yes. The SpectraLink SVP Server and the SVP support in the APs provide the guaranteed QoS required for enterprise-grade voice quality using SpectraLink wireless telephones. The SpectraLink SVP Server provides three core functions: prioritization of packets, timed delivery of packets, and admission control onto network access points. Over time, it is expected that industry standards will incorporate these three core functions and may become an alternative approach for implementing enterprise-grade QoS.

What is the maximum number of SpectraLink Wireless Telephones per network?

Each SpectraLink Telephony Gateway can support 16 users and eight simultaneous calls. Up to 40 Telephony Gateways can be used in conjunction with a SpectraLink SVP Server on a network, maximizing the system at 640 users and 120 simultaneous calls. When utilizing a native IP protocol interface, up to 16 SVP servers can be installed on a single system to support 850 simultaneous calls or approximately 8,000 SpectraLink wireless telephones, depending on traffic utilization requirements.

Do the SpectraLink Wireless Telephones support text messaging?

SpectraLink wireless telephones support SpectraLink's Open Application Interface (OAI). The OAI enables third-party messaging applications to write to the handset display, giving users the ability to view and respond to alphanumeric messages. The SpectraLink OAI Gateway connects to the application server either through a serial port or through the Ethernet network.

What are the differences between the different SpectraLink Wireless Telephone models?

The SpectraLink e340 Wireless Telephone is a four-ounce, compact handset that addresses the needs of the mobile business user in general office environments. The SpectraLink h340 Wireless Telephone is a rugged lightweight handset designed for use in 24-hour multi-shift environments such as the healthcare industry. The SpectraLink i640 Wireless Telephone is a rugged handset designed for louder team-based environments such as manufacturing, retail, and industrial environments. The SpectraLink i640 offers push-to-talk capability, battery management options for multi-shift applications, and at six ounces is small enough to be highly mobile yet rugged enough for the heaviest usage.

Will the SpectraLink Wireless Telephones support upcoming standards and telephony protocols not currently supported?

The SpectraLink wireless telephones are designed to be future-proof with new standards, features, and IP protocols in mind. SpectraLink is active in many standards committees and is committed to meeting market requirements as they relate to emerging standards and IP protocols. SpectraLink constantly monitors the enterprise voice communication market to ensure that widely adopted protocols and telephony switches are support by SpectraLink wireless telephones. Enhanced standards and telephone features can easily be implemented by utilizing the integrated TFTP client within the SpectraLink wireless telephones for software updates.

Push-to-Talk (PTT) Feature of the SpectraLink i640 Wireless Telephone

What is the impact on LAN and wireless LAN bandwidth?

A PTT multicast transmission will generate traffic that is nearly equivalent to a one-way IP voice call per AP on the wireless LAN subnet for each channel. PTT broadcasts are generally short-term in nature, so the overall impact on the network should be minimal. The use of a VLAN or subnet for the wireless LAN will help isolate broadcast and multicast traffic.

What is the impact on the SpectraLink i640 Wireless Telephone battery life?

The available talk time on the SpectraLink i640 is reduced at a faster rate when using the push-to-talk mode. The battery consumption is dependent on the recipient's volume settings and how frequently PTT broadcasts are originated. The reduction rate compared to telephone mode talk time is typically twice as high, although it can be as high as four times as much with maximum speaker volume. In other words, every one minute of PTT broadcasting consumes on average two minutes (and in the worst case four minutes) of talk-time related battery life.

Fortunately PTT conversations are short in duration, and the overall affect on talk time should be limited. The additional consumption of standby time related to the PTT mode is dependent on several network conditions. Any broadcast or multicast traffic, including multicast traffic from all PTT channels, will consume standby time at a faster rate than if no multicasting is used. Standby time can be impacted as much as 50% (40 hours maximum) depending on these factors. If PTT is not required by a user, better standby time can be achieved by disabling the PTT mode in the user menu. In addition, the wireless LAN can be placed on a separate VLAN or subnet to reduce the effects of broadcast and multicast traffic from devices in other network segments.

Can PTT operate without a PABX?

The SpectraLink i640 offers the push-to-talk option as an additional wireless telephone feature. The SpectraLink i640 has not been designed to be used primarily as a radio or walkie-talkie. The PTT feature only works in conjunction with an operational telephone switch interface. For the SpectraLink i640 to operate it must be registered to a SpectraLink Telephony Gateway, IP telephony server, or H.323 Gatekeeper (when in gatekeeper mode). As long as the SpectraLink Telephony Gateways are operational, PTT can be used if the PABX connections are lost.

What is the coverage of PTT and can it operate across a WAN?

The transmission coverage of the SpectraLink i640 wireless telephones is entirely dependent on the wireless LAN coverage, whether a standard PABX call is made or the PTT mode is utilized. The PTT mode is a wireless telephone feature and, as such, is subject to the same topology and quality of service considerations required by the SpectraLink i640 wireless telephones for proper operation with a telephony switch.

Does the PTT feature work through a headset?

A headset can be used with PTT broadcasts in the normal fashion. The volume keys adjust the headset volume when the headset is installed. The new headset volume selection will be retained. Normal PTT audio operations resume if the headset is removed.

Security

What security mechanisms are supported on SpectraLink Wireless Telephones?

SpectraLink wireless telephones support Wi-Fi Protected Access (WPA) and WPA2 using Pre-Shared Key (PSK), as well as legacy WEP (Wired Equivalent Privacy).

Do SpectraLink wireless telephones support 802.1x based security provisions like EAP-TLS or LEAP?

SpectraLink has evaluated a number 802.1x security methods. These advanced methods require a back-end authentication server to authenticate users and generate new keys. This authentication and re-keying process can take up to several seconds and is required each time a user roams from one access point to the next.

While this is taking place, the Wireless Telephone is not associated to an access point and there is an interruption in the voice transmission. Because this delay in the authentication process is unacceptable for a voice conversation, SpectraLink wireless telephones do not support 802.1x authentication.

Do SpectraLink wireless telephones support the 802.11i standard?

SpectraLink wireless telephones support the 802.11i standard through implementation of the Wi-Fi Alliance's WPA2 specification which is based on the 802.11i standard. SpectraLink announced support for WPA2 using Pre-Shared Key in the Spring of 2005.

What is the difference between WPA Enterprise Mode and Personal Mode?

WPA Enterprise Mode uses 802.1x authentication methods which require a back-end authentication server to authenticate users and generate new keys. This authentication and re-keying process can take up to several seconds and is required each time a user roams from one access point to the next. While this is taking place, the Wireless Telephone is not associated to an access point and there is an interruption in the voice transmission. This delay is the authentication process is unacceptable for a voice conversation. The WPA Personal Mode uses a pre-shared key for authentication purposes. This pre-shared key allows the client device and access point to negotiate authentication at the edge of the network thereby minimizing time delays and providing secure connections with acceptable QoS.

SpectraLink Voice Priority (SVP)

Can voice and data packets be transmitted across the wireless network at the same time?

Because all devices need to be compatible with the 802.11 standard, they are able to communicate in the same wireless network. However, when data and voice are competing for bandwidth it is necessary to have a prioritization method, such as SVP, that provides a controlled preference to voice.

How is voice quality ensured on a shared network?

SpectraLink Voice Priority (SVP) is SpectraLink's open mechanism for quality of service (QoS) on Wi-Fi networks. Adopted by the leading wireless LAN vendors, SVP guarantees audio quality in a shared voice and data network. The SpectraLink SVP Server, SpectraLink Telephony Gateway, SpectraLink wireless telephones, and wireless LAN access points work together to provide the clearest voice quality and the flexibility to manage radio bandwidth. SpectraLink Voice Priority is an open specification that is fully compliant with 802.11 standards.

Are SVP-compliant access points required if the wireless LAN is being used only for voice?

SVP is required to ensure the timing and delivery of packets. Without a method of prioritization for voice packets, the lack of a controlled delivery method will result in poor audio quality, even with only voice devices on the network.

If voice has priority, what happens to data traffic?

Data packets may be delayed due to voice traffic on the network, but these delays are no different from delays caused by additional data traffic. If it is necessary to guarantee a minimum amount of bandwidth for data applications, SVP allows a network administrator to set the maximum number of simultaneous voice calls over a single access point. A call will not handoff to an access point that is carrying the maximum number of sessions, but will handoff to other nearby access points. By limiting the number of active voice calls per access point, voice quality is ensured and a guaranteed portion of bandwidth is reserved for data.

Which wireless LAN vendors have implemented SVP?

SpectraLink has established technology partnerships with leading enterprise wireless LAN vendors, including 3COM, Alcatel, Aruba, Avaya, Cisco, Nortel, Symbol, and Trapeze. A complete list of compatible APs is available on our website.

Standards Compliance

Which 802.11 Physical Layer standards do SpectraLink wireless telephones support?

SpectraLink wireless telephones support the 802.11b standard which supports data rates up to 11 Mb/s operating in the 2.4 GHz band.

What is 802.11e, and do SpectraLink wireless telephones support it?

The 802.11e standard was developed to address quality of service (QoS) issues on wireless LANs. The standard was ratified in late 2005. 802.11e provides a compressive set of mechanisms for wireless QoS, portions of which will be implemented in various Wi-Fi products depending on their applications and target markets.

Do SpectraLink wireless telephones support 802.11a?

The 802.11a standard is a physical layer specification operating at 5 GHz and supporting data rates up to 54 Mb/s. Since 802.11a uses a different frequency band, it is not compatible with 802.11b. SpectraLink wireless telephones are not compatible with 802.11a networks. However, most enterprise wireless LAN implementations are using 802.11b, 802.11g (which supports 802.11b devices), or dual radio access points supporting both 802.11b/g and 802.11a.

What is Wi-Fi and the Wi-Fi Alliance?

The Wi-Fi Alliance is an industry organization that certifies interoperability of 802.11 APs and client devices. The term Wi-Fi is used to describe this technology. SpectraLink Wireless Telephone use Wi-Fi technology to communicate with compatible WLANs

Are SpectraLink wireless telephones compatible with 802.11g?

802.11g is the standard for adding higher data rate support in the 2.4 GHz band. Part of the standard requires that all 802.11g networks be backward compatible with current 802.11b devices. Therefore, SpectraLink wireless telephones using the 802.11b standard are compatible with 802.11g networks.

Do SpectratLink wireless telephones support standard VoIP protocols such as H.323 and SIP?

H.323 is an International Telecommunications Union (ITU) standard developed for video/audio conferencing that has been adopted by several VoIP vendors for call setup and signaling. SpectraLink wireless telephones can use H.323 for basic call capabilities. For a more feature-rich implementation, the SpectraLink wireless telephones can use proprietary IP protocols or operate in conjunction with a SpectraLink Telephony Gateway to access features from a traditional PABX. In March 2005, SpectraLink announced integration with Inter-Tel's Axxess platform using the SIP protocol. As additional IP-PABX vendors offer line-side SIP interfaces, SpectraLink will continue to develop and test SIP interfaces to meet those needs.