NAT-PCIe-8E1T1

The NAT-PCIe-8E1T1 is a PCI Express (PCIe) x1 add-in card with 8 Line Interfaces (LIF) for E1 / T1 to TDM conversion. The module joins into a PCIe slot as common, e.g. in a PC. On the other side it passes LIF functionality towards the user via RJ45 connectors. 

A Xilinx Spartan-7 FPGA with dedicated security features provides processing power. It is a cost-optimized device featuring a good amount of logic resources for implementation of the TDM data handling engine, that performs E1 / T1 data transfer via DMA into the host memory. It is accompanied by 32 MB SPI Flash for configuration purposes.

The FPGA owns a PCI interface internally connecting to a local-bus-system, which on turn delivers the information to the LIF unit. On this local-bus, these sections are memory-mapped:

• General control / status registers
• Clock/synchronization control / status block
• Access to E1-framer
• DMA engine control / status

The NAT-PCIe-8E1T1 uses only one PCI window (size less than 1MB) mapped into the host PCI memory.

Moreover, the FPGA’s PCI interface connects with the Diodes Incorporated PI7C9X112SL, a power-efficient, high-performance PCI-to-PCIe bridge. The PCIe interface of the bridge links to the PCIe interface of the carrier e.g., PC mainboard.

TDM data from the FPGA links to the Maxim Dallas DS26518 framer which converts to E1 / T1, and vice versa. This line interface unit supports both long-haul and short-haul lines as the ports are configurable independently.

The Texas Instruments LMK05028 PLL is supplied by a TCXO and a standard oscillator for clock generation.

The NAT-PCIe-8E1T1 aims on applications requiring up to 8 LIFs for conversion of E1 / T1 to TDM and vice versa. Typically, this comprises converting between PSTN and VoIP networks.

The NAT-PCIe-8E1T1 is the successor of the NAT-PCIe-XMC-4E1 board.

• Standard height, half-length PCIe x1 add-in card

Processing Resources

• Xilinx Spartan-7 FPGA
• Maxim Dallas DS26518 E1 / T1 framer
• Diodes Incorporated PI7C9X112SL PCIe-to-PCI bridge
• 32 MB SPI FLASH for configuration purposes

Connectivity 

• 8x E1 / T1 via RJ45 towards front panel
• MicroUSB at front panel
• PCIe x1 towards carrier board e.g., PC mainboard