Extension Cards: Extension cards are used to add more internal extensions to the PBX system. These extensions can be used for connecting desk phones, cordless phones, or other communication devices within the organization.
Digital Line Cards: Digital line cards are used to connect digital telephones to the PBX system. Panasonic offers a range of digital phones and line cards to support digital communication.
Analog Line Cards: Analog line cards allow the connection of analog devices such as fax machines, modems, and analog cordless phones to the PBX system.
ISDN Cards: Integrated Services Digital Network (ISDN) cards are used for ISDN connections, which provide high-speed digital communication capabilities.
VoIP Cards: Voice over Internet Protocol (VoIP) cards enable the integration of VoIP technology into the PBX system, allowing for IP-based communication and SIP trunking.

panasonic kx-ts3611bx

2.4 GHz digital cordless phone
Digital speaker phone
50-station phonebook & dialer
Caller ID with 50-station call log
Night mode: Disable ringtone during selected hours
2.4 GHz frequency hopping spread
Light-up indicator with ringer alert
Ringer ID – Customize your phonebook with a choice of preset ring tones
Illuminated display on handset
Wall mountable base unit
Built-in clock with alarm on handset
Handset locator
Battery life: Up to 5-hour talk time / 11-day standby
Rechareable batteries included
Includes 100-240V universal voltage adapter