The company reported a pro forma loss, excluding stock-based compensation, of $9 million, or 21 cents per share, wider when compared with a pro forma net loss of $4.4 million, or 13 cents a share, for the same period a year ago.
Wall Street analysts expected a loss of 24 cents a share, according to a consensus estimate tallied by First Call/Thomson Financial.
Quarterly revenue rose to $6.5 million from no revenue last year and just $1.1 million during the first quarter.
Sonus, which went public in May, announced four new customers during the quarter, counting BroadBand Office, Cybertel, USA Datanet and Z-Tel Technologies. The companies will use Sonus equipment in their voice networks.
The company manufactures network switching gear and "softswitch" software that enables communications carriers to deliver packet-based voice services. Global Crossing, Williams Communications and Intermedia use Sonus equipment.