This read-only integer serves as the virtual connection index for a channel on an AUSM (ATM User-to-Network Signaling Module) card, with the description noting that on the 4-port AUSM card the practically usable range narrows to 16-271 even though the syntax allows up to 1015. Admins use it to identify a specific logical channel when configuring or querying AUSM-specific connection tables, and should be aware that exceeding 271 on a 4-port card would be out of range for that hardware. For example, an admin provisioning a new PVC on a 4-port AUSM card must pick an ausmChanNum within 16-271, not the full 16-1015 the syntax nominally permits.