The TE420 PCIe card (3.3 volt) provides termination of up to 120 channels of voice/data across four E1, T1, or J1 interfaces in a PCIe x1 form factor. Selectable on a per-card/per-port basis, the TE420 allows E1 and T1 circuits to be mixed with full channel synchronisation. The Digium TE420 may be used in any available PCIe 1.0 compliant slot - 1x, x4, x8, and x16 without worrying about voltage selection or lane size.

The TE420 can be combined with Digium's VPMOCT128 Octasic DSP-based echo-cancellation module. The VPMOCT128 provides the benchmark G.168 algorithm and performs 128ms (1024 taps) of echo cancellation across all 96 channels in T1/J1 modes or all 128 channels in E1 mode. Bundled with the VPMOCT128, the product is known as TE420B.

The Digium TE420 has been designed to be fully compatible and integrated with Asterisk Business Edition, AsteriskNOW, and open source Asterisk.