CommScope (CTV) - Get Report raised its third-quarter guidance but cut its fourth-quarter outlook below expectations.

The Hickory, N.C., fiber optic and copper cablemaker says third quarter sales should be about $465 million. That is above the $427.5 million target the company had previously given and well above the $429 million analysts were looking for, according to Reuters Research.

The strong sales of all products will help widen operating margin to about 13.5% in the third quarter, or about 2.5 percentage points higher than prior guidance, the company said.

But book-to-bill was below 1, meaning orders weren't coming in as fast as shipments were going out. This slackened demand will cause a slowdown in the fourth quarter.

The company expects sales somewhere in the range of $370 million to $400 million and operating margin will narrow to about 9.5% in the fourth quarter. Analysts were expecting revenue of $398 million for the fourth quarter.

"We are pleased with our expected third quarter performance," CEO Frank Drendel said in a press release Tuesday. "We updated our revenue and operating income guidance primarily due to the strong third quarter sales volume. While we do not expect to duplicate this strength in the fourth quarter, we expect to deliver solid year-over-year growth in sales and operating income."

CommScope shares fell 32 cents, or 1%, to $31.65 in after-hours trading Tuesday.