How to make friends Cisco 7940 and TP-Link TL-SF 1008P in terms of power supply via PoE?

Question

Asterisk

There are 4 Cisco 7940 phones and a TP-Link TL-SF 1008P PoE switch. There is a desire to power tsiska through this PoE switch. The problem is that these ciscos use the “old” prePoE standard and just like that they don’t want to be powered from TP-Link. On the Internet, non-standard pinouts of patch cords were found, which supposedly should solve this problem, but no, they do not. Did anyone from Khabrovchan have a successful experience in this regard? If yes, then please share.

Answer 1

I also tried to flip the pairs, like here blizko.blogspot.ru/2012/04/poe-cisco-ip-phone-7940... As a result, the phone started working through the POE injector.
Then I found this solution blog.elmor.ru/raznoe/dorabotka-cisco-7940-dlya-rab...
As a result, I disassembled the phone, soldered a resistance of 25 kOhm, between 2 and 6 wire. And the phone started working through the POE switch deps.ua/katalog/poe-equipment/foxgate-s6008-g2-poe...
Direct patchcore or crossover doesn't matter.

Answer 2

Hello, I doubt that the pinout can help, the point is in the logic of devices with different PoE protocols .
If I'm wrong, correct me.