I'm probablely not describing this accurately, so I'm looking for a refresher and experience from anyone with these setups. 56K-Only ISDN ============= I heard long ago that digital switch service (non-PRI DSS T1 trunking) can be configured with a TC so you can support 56K-Only ISDN channels. Many of our POPs are in rural areas without PRI service, so this compromise would be a perfect solution for those seeking a digital link. D-Channel ISDN ============== This has a special name that I don't recall, but the concept is very cool. It uses the d-channel for both control and limited IP traffic. It provides an always-on / personal server concept that allows the customer to stay on 24/7 to receive realtime email, instant messages and simple remote service access without tying up two more larger channels. The benefit is similar to on-demand bonded service - where if you are sending enough to fill the first 56/64K channel, the second one comes up and bonds. But this takes it a step further. The customer starts with their small d-channel and sets up an IP session. And only turns up the regular b-channels as needed. I believe it can also be restricted to the d-channel only for cheap service and small transmissions like credit card transactions. :) Most here are disenchanted with 3COM's lack of support and vision, but this topic could breath some new life into our legacy hardware. Please add anything you know or can think of. Thanks --- Andy Dalrymple XMission Telecom Manager 801.303.0810 (8/8/02)