V401P Interface Card

The V401P cards are 4-span T1 or E1 cards manufactured by Varion. These cards were previously manufactured by Digium and replaces the V400P cards previously manufactuered by Varion. The figure below shows a picture of a V401P-T card.

(Click image to enlarge.)

The V401P cards have a lower level of signalling performance due to the lack of on-board HDLC functions. Transfers to the host processor over the PCI bus use PCI I/O ports and memory mapping.

Driver

These cards will soon be supported by the X400 driver.

The function of the V401P Channel driver is to provide for the termination of 2.048Mbps, 1.544Mbps, 64kbps and 56kbps digital paths. This driver provides direct access to the channelized or unchannelized T1 or E1 digital paths to OpenSS7 media and signalling protocol modules as well as providing T1 or E1 management, framing, coding, alarms, and synchronization.

Features

Following are some features of the V401P card:

4 T1 or E1 spans per card.
Dallas framer.
PLX PCI 9030 PCI bus chip.
Xilinx Spartan XC2S50 processor.
Raw transfer of octets from framers to PCI bus.
Uses OpenSS7 Soft-HDLC engine for SS7, ISDN and ISO.
96 channels per card (V401P-T)
124 channels per card (V401P-E).
Full span addressable.

Advantages

Following are the advantages of the V401P card:

Low cost.
PC Compatibility.
Released by Jim Dixon under the GNU Public License.
Open Hardware design: schematics, artwork and Gerber plots available.
Flash programmable Xilinx chip.
Field upgradable.
Supports a number of Open Source drivers.
Zaptel driver support.

Disadvantages

Following are the disadvantages of the V401P card:

Lower performance.
No on-board HLDC.
Cannot TDM switch on card or between cards, media channels must be transferred through host to switch between cards.
I/O Port and Memory Map instead of PCI DMA bus-mastering and burst transfers.
Does not run on high speed buses.
No integrated Ethernet for SIGTRAN and VoIP applications.
Synchronization per-card instead of per-system.

Ultimately, the performance limiting factor of the V401P cards is the bandwidth of the PCI bus and the ability of the processor to perform Soft-HDLC and TDM switching in software. A 350MHz processor is capable of processing the bandwidth of an entire V401P-E card (124 signalling links) with a combined link throughput of 8.192 Mbps.

For the OpenSS7 VoIP Switch, this performance is more than adequate. A medium grade 2GHz PC should be capable of handling 2 cards (248 SS7 links) with adequate excess capacity available for background operations.

These cards are very cost-effective and can provide 64kbps SS7 links at average incremental interface cost of approximately $4.00 USD per signalling link.

Disclaimer

Note: Some of the information in this hardware selection guide may be incomplete, incorrect, out of date, or inconsistent with the vendor's actual offerings. Also note that this hardware selection guide does not constitute an endorsement of anyone's product or service. The authors of the OpenSS7, their sponsors, agents and representatives will not take responsibility in it.

Please use good business sense when considering any vendor's products and consult with the individual vendor before making any decisions. Please do, however, investigate the product and service offerings of the sponsors listed on our Sponsors page: it is through your support of our sponsors that the OpenSS7 Project exists and is funded to continue.