描述
梯形图是使用得最多的图形编程语言，被称为PLC的第一编程语言。梯形图与电器控制系统的电路图很相似，具有直观易懂的优点，很容易被工厂电气人员掌握，特别适用于开关量逻辑控制。梯形图常被称为电路或程序，梯形图的设计称为编程。
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Nortel Operating Phone System
Nortel Passport NTNQ21AA, fully tested
NORTEL DS1402001-E5GS SWITCH 8010 10-SLOT CHASSIS
Nortel Baystack BS5510-48T Gigabit Switch 10/100/1000
1 Year Warranty – No Reasonable Offers Ever Refused!
Nortel CICS System w/Startalk Flash & 7 Phones – USED
Nortel CS1000E Daughterboard 96 NTHU61AA NTDW64AAE5 NEW
2 Nortel Optera NTN414AH VTX-48
Nortel Call Pilot 150 Voice Mail With 32 Mailboxes Rele
Nortel Norstar CICS Office Phone System w/ 10 T7316 VM
