Protection One Inc., a Lawrence-based provider of monitored-security services, announced Tuesday that it had spent more than $1 million expanding and upgrading a monitoring center for commercial and national accounts in Irving, Texas.

The center is home to Network Multifamily Security Corp., which is a Protection One subsidiary and serves more than 315,000 multifamily properties nationwide.

Protection One’s corporate headquarters is located in the I-70 Business Center in North Lawrence.