As stated in the Q and A pages of IATA’s Lithium Battery Guidance Document available from IATA’s website, the telephone number required on the Lithium Battery Handling Mark can be a 24-hour monitored number, or other normal office hour number provided a person knowledgeable of the lithium batteries being shipped is readily available. It does not have to be monitored 24 hours.
The telephone number must start with the country code. (Example: 81-47-335-7924). Furthermore, USA have withheld approval of the new Lithium Battery Handling Mark by Executive Order, so until the matter is cleared for shipments to, from or through the United states and when transporting on a U.S. carrier, you will use the old label which have a grace period of two years until 31 December 2017. This also applies to the new Class 9 label (DGR Figure 7.3.X).