Hardware

The Linksys PAP2 is an analog telephony adapter

Analog telephony adapter

An analog telephony adapter, or analog telephone adapter, is a device used to connect one or more standard analog telephones to a digital telephone system or a non-standard telephone system....

 (ATA), which allows for the connection of up to two analog telephones to a softswitch or VoIP carrier using Session Initiation Protocol

Session Initiation Protocol

The Session Initiation Protocol is an IETF-defined signaling protocol widely used for controlling communication sessions such as voice and video calls over Internet Protocol . The protocol can be used for creating, modifying and terminating two-party or multiparty sessions...

 (SIP). The physical connections on the device are two RJ11 jacks for the telephones and one 8P8C jack for ethernet. The ethernet connection is 10 Mbit/s, half-duplex. The device is configured through a web interface. Each analog telephone is presented as a distinct SIP user.

The Linksys PAP2 is based on the Sipura SPA-2000 ATA design. The device is designed around an ESS Visba 3 (ES3890F) chipset and Realtek RTL8019AS 10BaseT Ethernet controller.

The original PAP2 has been discontinued. The PAP2 version 2 and the PAP2T are successors with similar capabilities, the PAP2T is reported to have twice the memory of the PAP2 version 1. They are different enough that they have distinct firmware. The PAP2 version 2, unlike the others, runs Linux (Linksys has released source for the GPLed portions of the firmware).

As of late 2011, Cisco has introduced the SPA112, which supersedes the PAP2T, and the SPA122, which replaces the SPA2102 (these latter two include router functionality.)

Hardware and revisions

Cisco Linksys PAP2

Version	RAM Ram -Animals:*Ram, an uncastrated male sheep*Ram cichlid, a species of freshwater fish endemic to Colombia and Venezuela-Military:*Battering ram*Ramming, a military tactic in which one vehicle runs into another...	Flash memory Flash memory Flash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...	FXS Ports	Notes
1.0	2 MB	1 MB	2	Power adapter is 5V DC 2.0A
2.0	16 MB	8 MB	2	Power adapter is 12V DC 1.0A. Runs Linux.
3.0	16 MB	8 MB	2	Power adapter is 12V DC 1.0A. Marketed as the PAP2T.

Bundled units

The PAP2 has been bundled with popular VoIP services such as Vonage

Vonage

Vonage is a publicly held commercial voice over IP network and SIP company that provides telephone service via a broadband connection. The company's name is a play on their motto "Voice-Over-Net-AGE"....

 and AT&T

AT&T

AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...

’s CallVantage offering. These may be locked to such VoIP services but an unlocked version of the device (which is directly comparable with the Sipura device), is also available. This is referred to as the PAP2-NA or PAP2T-NA or PAP2-EU.

Locked units usually have the second line inaccessible, unless the provider specifically configures it (for example if you had two Vonage lines).

Firmware modification

For a while, people were able to unlock the "locked" devices offered by providers such as Vonage, however since November 2005, a firmware update has been released which "corrects" some of loopholes being used to unlock the devices. In one particular instance, Vonage have actually withdrawn some of their PAP2's from UK retailers such as Comet

Comet Group Plc

Comet is an electrical retailer in the United Kingdom, which is owned by OpCapita and a series of investors, after its sale by Kesa Electricals. The group was founded in 1933 by George Hollingberry in Hull as Comet Battery Stores Limited...

 in order to replace them with units containing the newer firmware, so that there is little chance of them being unlocked. As of 2007, all Vonage PAP2 devices can be unlocked. However, PAP2s, including PAP2-NAs locked to other providers generally cannot be unlocked without either that provider's encryption key or the administrator password.

Linksys datasheet

The Linksys Internet Phone Adapter provides telephone service through an
Internet connection. It connects to the Internet gateway and provides two telephone jacks for telephones or fax machines. Each phone jack has independent phone service and phone numbers. The Linksys equipment provides other features and benefits associated with Internet telephony.

Minimum requirements

• High-speed Internet connection (cable/DSL/other)
• Broadband router or gateway
• Activated Voice over IP Service
• Regular analog touch-tone telephone

Supported codecs

• G.711
  G.711
  G.711 is an ITU-T standard for audio companding. It is primarily used in telephony. The standard was released for usage in 1972. Its formal name is Pulse code modulation of voice frequencies. It is required standard in many technologies, for example in H.320 and H.323 specifications. It can also...
  
   (u/a)
• G.723
  G.723
  G.723 is a ITU-T standard speech codec using extensions of G.721 providing voice quality covering 300 Hz to 3400 Hz using Adaptive Differential Pulse Code Modulation to 24 and 40 kbit/s for digital circuit multiplication equipment applications...
  
   (5.3/6.3)kbps
• G.726
  G.726
  G.726 is an ITU-T ADPCM speech codec standard covering the transmission of voice at rates of 16, 24, 32, and 40 kbit/s. It was introduced to supersede both G.721, which covered ADPCM at 32 kbit/s, and G.723, which described ADPCM for 24 and 40 kbit/s. G.726 also introduced a new...
  
   (16/24/32/40)kbps
• G.729a (only one line at a time due to onboard CPU power)

External links

• User Guide - User Guide from Cisco
• PAP2T support - Information about the PAP2
• linksys GPL source code
• Cisco SPA112 Specifications