The use of 802.11 to transport delay sensitive traffic is becoming increasingly common. This raises the question of the tradeoff between buffering delay and loss in 802.11 networks. We find that there exists a sharp transition from the low-loss, low-delay regime to high-loss, high-delay operation. Given modest buffering at the access point, this transition determines the voice capacity of a WLAN and its location is largely insensitive to the buffer size used.