Binghamton, NY Nov ten, 2009 #7 I'm not familiar with meter operation, but I would suspect that it has to send the switching voltages (13v for odd and 18v for even). And, if you need to see one other sats it must send out the 22khz tone. I recommend friends https://scrapbox.io/dienphucthinh22-18558335/cap_tin_hieu_rs485_tai_dien_phuc_thinh