Digium Analog Cards

Analog Cards

Analog cards are available in various capacities, ranging from a single port (which connects a single analog telephone line and thus a single telephone call) up to a maximum 24 ports.

Low density analog cards generally use the same kind of connector as most home and small business phone devices: the RJ-11 jack. Each jack on the back of the card takes a single RJ-11 phone cable. The other end of the cable plugs into a telco phone jack or an analog port on the legacy PBX.

Analog ports can either connect to an analog line from the telephone company using a port connected to an “FXO” module, or can power and control an analog phone using an “FXS” module.

Most analog card manufacturers build analog cards with interchangeable modules. By including both FXO and FXS modules, a card can offer both FXO (line) and FXS (phone) capabilities. This makes it simple to build an Asterisk-based application that can both connect to the PSTN and control analog devices like fax machines, credit card terminals or TDDs.

High density analog cards often use an RJ-21 (or “amphenol”) connector and require an opposite gender RJ-21 connection from the telco or PBX.

FXS Ports In Analog Gateways

VoIP gateways built to connect legacy equipment (PBXs, key systems) with VoIP services generally use FXS ports. FXS ports provide dial tone and line voltage to a phone, exactly like the phone company’s line does. This means that FXS ports can be connected to “line” or “trunk” ports on the legacy system and can emulate telco analog lines.

FXO Ports In Analog Gateways

Using FXO (line) ports to connect analog PBX ports with VoIP phones or remote VoIP servers is another common Asterisk gateway application. In this scenario, analog station ports on the PBX are connected to FXO ports on the Asterisk gateway card. When the PBX sends a call to the cross-connected analog station port, Asterisk forwards it as a VoIP call to the designated endpoint.

The limitation of this arrangement is the one-extension/one-port nature of PBX analog stations. The signaling capabilities of analog station ports are generally very limited. This means that the port can only respond to calls to the single extension number with which it is associated. It therefore cannot be used as a shared connection between the PBX and the Asterisk (and whatever connects with the Asterisk).

Digium Analog Card Family

The Digium analog card family is made up of three groups of products depending on the number of ports you will need in your system.

TDM410P/AEX410
The TDM410P (PCI) and AEX410 (PCI-Express) cards support up to four analog ports in any combination of FXO and FXS ports. Using an industry-standard bursting, bus-mastering interface chip that is found within millions of PC systems worldwide, and Digium VoiceBus™ technology, the TDM410 eliminates the requirement for external gateways, with industry-leading performance and price. The trunk and station modules are interchangeable, allowing the creation of any combination of interfaces. The optional hardware echo cancellation module provides 1024 taps (128 milliseconds) of echo cancellation for superior voice quality on both trunk and station interfaces. Scaling of this solution is accomplished by adding additional TDM410 or other Digium analog interface cards.

TDM800P/AEX800
The TDM800P provides an industry first with 8 standard two-wire, RJ-11 interfaces on a single PCI bracket. This eliminates the need for multiple brackets, external dongles, or splitters. In doing so, the TDM800P reduces part complexity, cable clutter, and points of failure.

The TDM800P contains two module banks. Each bank supports up to four analog interfaces. The module banks may be filled either with one standard Digium® quad analog module (FXS – S400M, FXO – X400M), or up to two standard Digium® single analog modules (FXS- S110M, FXO – X100M) enabling the creation of any combination of ports

The optional hardware echo cancellation module provides 1024 taps (128 milliseconds) of echo cancellation for superior echo cancellation on both FXO and FXS interfaces.

If the hardware echo cancellation module is not installed, the TDM800P may be used in conjunction with Digium’s High Performance Echo Cancellation (HPEC) software, a commercial and toll quality hybrid echo cancellation solution. Digium’s HPEC provides 16ms to 128ms of selectable near-end ITU G.168 compliant echo cancellation in software.

Using this card in concert with Digium’s Asterisk® software, standard PC hardware, and the Linux® OS, you can create SME or SOHO telephony environments capable of satisfying the needs of small or medium business applications at an industry-leading price.

TDM2400P/AEX2400
Using Digium’s Asterisk Open Source PBX software and standard PC hardware, one can create a telephony environment that includes all the sophisticated features of a high-end business telephone system.

Using an industry-standard bursting, bus-mastering PCI interface chip that is found within millions of PC systems worldwide, and Digium VoiceBus™ technology, the TDM2400P eliminates the requirement for separate channel bank and T1 interface cards, at an industry-leading price. The quad-FXO and quad-FXS modules are interchangeable, allowing the creation of any combination of interfaces. The optional hardware echo cancellation module provides 1024 taps (128 milliseconds) of echo cancellation for superior echo cancellation on both FXO and FXS interfaces. Scaling of this solution is accomplished by adding additional TDM2400P cards.