Hospitals and labs are notorious for expensive, proprietary equipment that cannot be networked. A blood analyzer or an MRI interface that uses a 9-pin serial port is a compliance nightmare (HIPAA, FDA tracking). The Samba 139 solves this by encrypting the serial data stream using or HTTPS , allowing legacy devices to operate within modern, secure medical networks.
In a controlled lab environment (like Metasploitable 2), Port 139 is often used to demonstrate SMB vulnerabilities. Preparation for Sending by Scan to Folder - Ricoh Support samba 139