This read-only string reports the number of calls handled, broken out per port and packed into a single comma-delimited list, giving a gateway-wide view without querying the per-port table individually. Admins use it to spot ports with unusually high or low call counts at a glance, which can indicate hunting-group imbalance or a stuck/idle port. For example, a string like '15,15,16,0,15' would flag the fourth port as having handled zero calls, worth investigating for a hardware or trunk-group misconfiguration.