Home Vehicle Compliant. HVC is shown only on the Quiet Lines models, which were intended to comply with proposed congressional legislation concerning suburban noise pollution. The legislation was drawn up and proposed in committee hearings but never enacted. However, IH was ready if it had been.Have a 1250 here with a 0630 kind code. In the FAQ that shows up. It indicates it is a 1250 (hvc). Anyone know what the hvc means?