• Grows from 3 lines & 8 phones to 6 lines & 24 phones.
• Provides modern features like Caller ID, Voice Mail Integration, message waiting lights, DISA, fax detection
• Handles up to FOUR door speakers with remote unlocking and distinctive ringing sound. Door speaker boxes can also be used for baby monitoring.
• Works with 7000-series phones and earlier analog multi-line proprietary phones, or single-line phones and devices (NOT 7200 or 7400-series digital phones).
• May be weird with ancient KX-T30830 and similar phones.
• New KX-T7135 phone with illuminated display requires TX-TA624-2 or later version, for use on first eight station ports ("extensions"), but will work fine in expansion modules of earlier 624 systems.
• Although the 616 can be sold by any Panasonic dealer, we suspect that most are sold by companies that are primarily in other fields, such as alarm systems or home automation, and are not certified to sell Panasonic's digital systems.
• When you compare features and dollars, the 624 is often beaten by the digital 308 and 816.
• Main reasons to buy: you need more than two door intercoms, or if you need a bit more modem speed, or you want to use a lot of inexpensive multi-line phones, or you want to replace an analog KX-T30810 or KX-T61610 control unit..
• Main reasons NOT to buy: no programming or backup by PC, phones are two generations older than current digital models.

Just when we thought the whole world has gone digital, those foxy folks at Panasonic surprise us with a new feature-rich expandable analog control unit, that does a few tricks the digitals can't do.

Out of the box, the KX-TA616 control unit provides a big collection of features  -- including features like text messaging that were unavailable on Panasonic analog systems in this size range and it can be easily updated and enhanced to keep pace with changing needs. Adding features or capacity is easily accomplished with plug-in circuit cards and system programming.

Programming is by display phone, only. The DB-9 serial port provides information on phone calls ("SMDR"), but it is not interactive for programming or back-up. As with the digital systems, programming access is controlled by password, not by flipping a switch on the control unit -- a big advance over the previous analog systems.

The basic KX-TA616 supports three outside lines and eight phones or gadgets (3X8 configuration). As your needs increase, up to two additional boards can be stacked up on the motherboard. A KX-TA62470 board adds another eight phones to the system for a 3X16 configuration; or a KX-TA62477 board adds three outside lines and eight additional phones lines (6X16). Or both cards can be added for a maximum system configuration of six outside lines and 24 internal ones (6X24). You can only add one of each type of card.

The KX-TA308/TA616/TA624 are hybrid designs, meaning that you can connect either Panasonic 7000 series multi-line telephones or single-line devices such as standard telephones, fax machines or modems to any station port in the system without special hardware.

• Caller ID is provided by the KX-TA 30893 add-on module. The caller’s name and phone number can appear on the display of a Panasonic KX-T7030, 7130 or 7135 phone. Up to two CID modules can be added and each supports up to three  CO lines. CID info can NOT be sent to non-proprietary phones and displays, and CID does NOT work with Call Waiting. Display of name may not be available with some Caller ID services. The system can log up to 20 unanswered calls per extension. With the help of Caller ID and the Call Log feature you can identify those callers when you come back to your desk, allowing you to easily return the calls.
• Voice Mail Integration
  This feature, absent from the analog 308 and 616, makes sure that messages reach the right mailboxes, and speeds up message retrieval. (Uses in-band signaling.) You also have message-waiting lights, which did not work on the analog 308 and 616. Give your business a highly professional image and added efficiency with such features as automated attendant, voice mail, interview service and custom service scripts, matched to the needs of your business and your callers. Setup is particularly easy with the new, inexpensive
• Direct Inward System Access (DISA)/Fax Detection
  The KX-TA 30891 module saves you time and money with three important built-in capabilities. (1) DISA is  a simplified "auto-attendant" feature ("press one to place an order...") with two custom 30-second outgoing messages. Callers have single-digit access to phones or departments at any time during or after the outgoing message. You can use different announcements for different lines, or groups of lines. (2) When you’re out of the office, you can still make a phone or fax call as if you were sitting at your desk. Dial into the system and calls are handled as if they were made from an inside extension, making billing and bookkeeping simpler. Callers who want to access the system's outside lines or place intercom calls can be required to dial a security code first. (3)  This module can also detect an incoming "CNG" fax tone and automatically transfers the call to a designated extension. This saves money because no separate dedicated fax line is required, when a fax is in use, no one can interrupt the data flow.
• Door Intercom and Door Opener
  Using the KX-TA30860, the system provides intercom and remote unlocking at up to four doors. A distinctive ring alerts people inside that a visitor has arrived at any of four entrances. Anyone can then speak to the guest and remotely "buzz" them in with the telephone keypad. You can also use the door speakers to monitor a baby, or children in a playroom.
• Dual Port Usage
  The KX-TA308/TA616/TA624 System is ready for expansion right from the start. You can easily connect a Panasonic proprietary telephone and a single-line device, such as a modem or answerer or cordless phone, simultaneously to any phone jack. You can dial a call from your PC, and then use the phone to speak.
• Flexible CO Line Buttons
  The central office (CO) line buttons on each telephone in the system can be programmed to suit the specific needs of the person who uses that phone. You can  program buttons for one-touch intercom calls, one-touch automatic dialing or one-touch access to features, such as paging.
• Automatic Redial
  At the touch of a button the phone automatically redials the last number called. This feature can be extremely helpful when you're trying to get through to a busy party.
• Proprietary Cordless Phone Integration
  The Panasonic works very well with a KX-TA308/TA616/TA624 Systems. The KX-T7880 offers flexible buttons with indicators that can be programmed to access central office lines. It also features intercom, redial, conference, transfer and hold buttons on the cordless handset, providing easy access to these functions even while you're away from the base unit. You can also use the newer which can handle more lines and has a display and headset jack. 
• Single Line Device Integration
  The KX-TA624 allows you to connect many types of telephone equipment, such as answering machines, cordless phones, fax machines and computer modems, without the need for costly additional circuit modules or new wiring.
• Station Message Detail Recording (SMDR)
  By connecting a serial printer to the system, or by attaching a call accounting system, you can obtain a record of calls. Know who called where, when, and for how long. Account codes may be assigned to keep track of costs to be billed to clients, employees, projects or departments.
• Toll Restriction
  The KX-TA616 can be programmed to prohibit unauthorized outgoing long distance calls by restricting specific phones from accessing specified area codes or exchanges.
• Time (Day/Night/Lunch) Service
  The system can automatically switch between day, night and lunch modes at a programmed time every day, for changes in ringing patterns. The modes can also be changed manually by the operator or manager at any desired tim e.
• Other Features:
  CO Line Groups, Account Codes, Paging, Music On Hold Input, Executive Override (barge-in), Conference Calling (attended and unattended)