Comdial Executech I System Models: PBX / KSU  308X - 616 - 616B - 616X - 816X - 824
Comdial Executech I Phone Models: 3503-AB, 3503-BB, 3508-AB, 3508-BB, 3593-AB, 3593-BB, 3598-AB, 3598-BB, 6414-AB, 6414-BB, 6414-PG, 6414S-PG, 6414S-AB, 6414S-BB

Comdial Executech II System Models: PBX / KSU  N0308 - N0616 - N0820 - N1024 - N01024 - 1432 - 1432B - 2264 -2296 - E34PT - E60PT - E80PT
Comdial Executech II Phone Models: 3502, 3500, 6600-PG - 6600-AB - 6600-BB, 6600S, 6614E-PG, 6614-AB, 6614-BB, 6614-PG, 6614S-PG, 6614T-PG, 6620-PG, 6620-BB, 6620-AB, 6620S-PG, 6620T-PG, 6622-PG, 6622-BB, 6622-AB, 6622S-PG, 6622T-PG, 6706X-PG, 6706S-PG, 6706X-BB, 6714X-PG, 6714S-PG, 6714X-BB, 6714S-BB, 6714S-AB, 6700S-PG

The Comdial Executech series phones are all analog phones that will only work on the Comdial Executech, 2000 and Hotel systems. The older Executech I phones can work on most of the Executech II systems, however the station ports must be programmed to use the older phones and once programmed those phones will not work with the newer Executech II phones. If you plug in the wrong phone into a port not programmed correctly the phone will not work and usually the lights will rapidly flash in a random pattern. Executech II phones will not work on the Executech I systems.

The biggest problem with repairing the Comdial Executech phones is the keypad. The older phones all used a conductive rubber keypad that makes contact (when pushed down) with a grid pattern on the keypad circuit board. The electric current that flows through these buttons is tiny but still a bit too high and will cause the rubber to break down over time. The earlier 66XX series used conductive paint instead of conductive rubber, however these also broke down over time. In either case, bits of material build up on the circuit board and eventually cause intermittent shorts that are worsened by heat and humidity. When a button is shorted out the phone thinks someone is holding that button down and will not pay attention to any other button presses. Sometimes the connection is intermittent and the phone may pick up lines on it's own. The most commonly effected buttons are the HOLD, ITCM, SPKR, and the first few CO line buttons. The newer style Executech phones (with a T, E or X in the part number) used two plastic sheets that sandwiched conductive tracings. When pressure was placed on the "buttons" the tracings would touch. These keypads were much more reliable however if any liquids managed to get into the phone the resulting corrosion can kill the keypad and the keypad has to be replaced rather then repaired. Unfortunately at the same time the keypads were changed, the rubber part was also changed and the lettering wears off much quicker so you can not see the number pad or "HOLD" etc... In all cases, Comdial put the keypads together by melting plastic tabs. To repair the keypads or even just to see if the keypads need work you must break apart the keypad housing. When the repair or inspection is complete, putting the keypad back together can be the most difficult step. It must be clamped and glued together. Not just any glue will do either, the glue must be flexible and stick to ABS plastic as well as the circuit board and hold up to some pressure. You also want the option to be able to take it apart again if necessary so using an entire tube of glue is not a good idea.

Except for the keypad, the Comdial Executech phones are very sturdy and reliable. At this point they are all at the age where if they have not been repaired already, then they need repair work. Unfortunately there are not very many places that can or are able to do an adequate job repairing the keypads. The 67XX series phone sometimes have problems other than the keypad but most common issues like the hookswitch, line jack, speaker and microphone are all very sturdy. 

Tips:    Comdial manuals  -    Comdial user guides   -   Comdial repair
A Comdial 6706 phone can be replaced using a 6620 phone without any re-programming of the buttons. The 6620 phone has a few more buttons then the 6706 and it is a little bit larger.

You can not get Caller ID to display on any Comdial Executech phone system. There were some systems that could handle it but they require special add-on equipment that has not been manufactured for years and was not very popular. (You will not be able to find it)

The original older handsets (from the 35XX phones ) are different from the newer phones (66XX, 67XX phones). You just need to worry about the ash and black color handsets. Some of the older handsets will sound dull and echo when used on the newer phone sets.