A LOT of foreigners in China regularly dial a number in the United States and when the telephone rings there they promptly hang ups before it is answered. The reason? They are contacting a call back service to avoid the excessively high charges in China. The call to America triggers an automatic call back and within a few seconds the telephone user in China is linked to a US dial tone and can ring any number in the world as if calling from the United States - at a much cheaper rate. This has created so much competition and lost business for the Chinese telephone company that [Beijing announced on Saturday it would lower its charges for international calls by 30 per cent as from today. Thus, calls from [China to western Europe will be reduced from 29.55 yuan (£2.20) per minute to 20.76 yuan (£1.55) - still almost double the call back service charges, but cheaper than a call from Ireland to China, which costs £1.74 per minute.