This will be a general list by manufacture of the phones I repair. Have been repairing Business phones starting in 1994. Because of the amount of plastic and time I will not buy any phone to scrap.
All LCD boards are good but most are very small.
Intertel: Good boards
Comdial: Good [some of the Executech key boards are gold plated, tracings and contact grids on both sides]
Toshiba: Most low grade [Most EKTXXXX are low grade DKT 20XX low grade DKT 30XX Good]
Nortel: Good but a lot of the boards are very small [around 2" X 3"] and use a Mylar for the keyboard.
Panasonic: Most are low grade
NEC: most are good
AT&T, AVAYA: Good boards
Vodavi: Most are good
Executone: Most are good [CX and Equity are low grade]
Macrotell: I can check but as I remember most are low grade.
KSU/Control unit boards
Almost all are Telecom grade
Avaya definity cards: Almost all will be Telecom grade [you may have to remove small transformers] and weigh slightly over 1lb each [$4 - $7 each as scrap at this time]
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