Review: Sipura SPA-2100 Analog Telephone Adapter

Sipura Analog Telephone Adapter

Sipura Analog Telephone Adapter
Summary Extremely configurable SIP V2 router with single 10Mbps LAN port and two FXS (phone) ports
Update 6/25/2005 - Corrected incorrect QoS test method
Pros • Extensive SIP configuration options
• Built-in NAT router
• Effective QoS
Cons • Limited routing features
• Slow routing speed
• Only one 10Mbps LAN port

VoIP insiders know that Sipura supplies the VoIP know-how for Linksys' current line of VoIP products. They have done such a good job of it that Cisco's Linksys division bought the company. I recently used the Sipura SPA-2100 Analog Telephone Adapter in a review of BroadVoice's Bring Your Own Device (BYOD) service and thought it rated a closer look.

The 2100's product name is somewhat misleading since the VoIP term "Analog Telephone Adapter" generally denotes a device with one or two RJ11 jacks that accept regular analog phone or fax devices ("FXS" or "Foreign Exchange Station" in VoIP lingo), plus an Ethernet port for connection to a broadband modem or router. But a glance at the complement of jacks on the 2100's rear panel (Figure 1) shows something else is afoot.

Figure 1: Sipura 2100 back panel

The 2100 would be more accurately termed a VoIP router, since it has 10Mbps Ethernet WAN and LAN ports and contains a basic NAT router in addition to its extensive array of SIP V2 functions. This means it can share a broadband connection among multiple Ethernet devices, although, with only the single LAN port, you'll need to provide a switch to connect more than one.

The main negative about the 2100's compact and attractive silver-gray plastic packaging is that all indicator lights are on the rear panel. This happens to work out well for my preference of indicators and Ethernet jacks on the same panel, but doesn't match the typical consumer device configuration of lights on the front and connectors on the rear.

Figure 2: Sipura 2100 board top
(click image to enlarge)

Figures 2 and 3 shows the top and bottom of the 2100's board. Most of the heavy lifting is handled by a Sipura SIP316F custom chip. Add a pair of

Figure 3: Sipura 2100 board bottom
(click image to enlarge)