Null modem is a communication method to directly connect two DTEs (computer, terminal, printer, etc.) using an RS-232 serial cable. The name stems from the historical use of RS-232 cables to connect two teleprinter devices or two modems in order to communicate with one another; null modem communication refers to using a crossed-over RS-232 cable to connect the teleprinters directly to one another without the modems.
It is also used to serially connect a computer to a printer, since both are DTE, and is known as a Printer Cable.
The RS-232 standard is asymmetric as to the definitions of the two ends of the communications link, assuming that one end is a DTE and the other is a DCE, e.g. a modem. With a null modem connection the transmit and receive lines are crosslinked. Depending on the purpose, sometimes also one or more handshake lines are crosslinked. Several wiring layouts are in use because the null modem connection is not covered by the RS-232 standard.

You do not have permission to view the full content of this post. Log in or register now.
  1. B

    Help NULL sa bagong biling SUN sim!?

    Hi! Bagong biling sun sim. Registered ako sa TU50. Lahat ng TELETUBBINS config ko, NULL ang lumalabas. Ayaw mag connect. Frustrated na ko 😞 Ngayon nagbalak ako gumawa ng ibang account sa Trinity vpn, SSH-SSL ayaw din. Ako lang ba nakakaranas nito? Anyone na pwede ako tulungan? Huhu
  2. S

    Closed How to root?

    hi po mga ka phc pano po ba e root ang SAMsung note 3 SM-N9005 na kahit walang pc?? na try ko po yung king root pero hangang 70% lang cya d na cya nag po proceed, at after mag reboot babalik ukit sa 15% any suggestion plzzz?
  3. A

    Help Opera mini 4.2 ui d33 error null

    Ask ko lng po kung paan0 ayusin tong error n to, d33 error null, lumabas yan sa kalagitnaan ng pg lo loading.. At pg mg view ng mga photos.. Pages .. Bkt kya my error n gn2