Remote made busy: RMB

Remote made busy or RMB is a common disposition for a channel if you're dealing with hardware issues. The carrier may see a DS-0 in this state when your hardware independently locks out the channel. Channels in an RMB state can sometimes be corrected if your carrier takes down the specific channel and resets it (this process is commonly called bouncing a channel). If your carrier can't bring the DS-0 back into service by bouncing it, the only way to restore the channel is for you to reboot the hardware. If this condition is chronic, contact your hardware vendor to test the hardware. It's better to find the problem when it's minor, than to let it go until the point at which the channel won't come back to life after you reboot.

D channel made busy: DMB

The D channel made busy state is used only with ISDN circuits. Only ISDN circuits have D channels designated for signaling, and that is why non-ISDN circuits can't have channels in this state. When the D channel made busy state appears on an ISDN circuit, the entire circuit is down. The D channel handles all the logistics of call setup and teardown on an ISDN circuit, and without the overhead, the circuit can't function.

Tip This condition can be the result of your hardware having issues (see the section on RMB, earlier in this tutorial), your carrier having issues, or an ISDN protocol mismatch.