Nortel Meridian NT5D12AB Dual T1 DTI/PRI Card. Works with Meridian Option 61C & 81C systems. The dual port DDP is a single-slot circuit card that provides two ports, each of which is configurable in any combination of 24 DTI channels or 23 B+D PRI channels. The DDP replaces one (1) QPC414 ENET plus two (2) QPC720 PRI/DTI packs providing equivalent functionality. An optional dual-port daughterboard (NTBK51AA) is used for PRI applications as an alternative to existing external D-channel handler packs and associated cables.