The U.S. Coast Guard has asked wireless phone service providers to remove the key sequence *CG from their services and reroute the calls to any local 911 service.
The key sequence was introduced in the early 1990s. Originally, the service worked like dialing a 911 public safety answering point (PSAP), routing the call to the nearest PSAP location. By keying *CG, calls from mariners in distress would be routed to the Coast Guard.
Depending upon the area code of the phone initiating the call, however, the call might not be routed to the nearest Coast Guard Station. For example, by dialing from a phone with a 305 area code a mariner might reach the Coast Guard in Miami, despite the fact that he was in trouble in New York Harbor. This might result in serious delays in response time. Multiple cellular services and poor cellular coverage also contributed to the decision to discontinue *CG service. The only exception to this is Alaska, where the Coast Guard has a single routing number for *CG.
The Coast Guard recommends that mariners use VHF/DSC radios to broadcast distress calls, noting that many VHF radios allow the Coast Guard to track a distress call via GPS. Also, by broadcasting the distress call over VHF there is a chance that a nearby vessel could overhear and might be able to render immediate assistance.