RJ-11 is a standard telephone (non voice over IP)
RJ-11 is the standard connector utilized on 2-pair (4-wire) telephone wiring
There are RJ-11, RJ-12, and RJ-45 connectors. RJ-11 is typically used for telephone lines, while RJ-45 is used for NICs.
RJ 15
RJ11 is a physical interface often used for terminating telephone wires. It is probably the most familiar of the registered jacks, being used for single line POTS telephone jacks in most homes across the woeld
RJ-11 Is typically used for ADSL lines here in the UK, and maybe in Europe too.
rj11
You use a Rj-45 connector with twisted-pair cabling in an Ethernet LAN. Rj-45 is a connector with a 4 5 wiring sequence.
RJ-11 Port-Modem cards in desktop computers provide two phone jacks called RJ-11 jacks so that one can be used for dial up networking and the other jack can be used to plug in an extension telephone.Daniel Allen
RJ-45 Ethernet, RJ-11 Modem
RJ 11
RJ stands for registered jack. There are a no. of RJ's that we use for e.g., RJ-9 ,RJ-11 RJ-12, RJ-45, RJ-48 etc
Differences between RJ-11 and RJ-45: • RJ-11 (connectors) have positions for 6 wires (3 pairs), used primarily used for voice transmission over typically 2 ranging up to 6 of the wires. • RJ-45 has 8 wires (4 twisted pairs), primarily used for data transmission over 4 to 8 wires. • Connectors are physically different sizes. That said, they have many similarities as well. Some you may not have thought of: • RJ-11 and RJ-45 both have pin spacing that is identical. This is by design. • RJ-11 and RJ-45 both have connectors of identical height. • RJ-11 and RJ-45 both use the same shape and size centralized plastic locking pin. Thus, the only sfdifference being RJ-45 allows for 2 extra pins and is a slight bit wider. So In a pinch, an RJ-11/14 6 wire cable can be used to connect two RJ-45 devices provided that that RJ-11 cable has all four or six wires and the RJ-45 socketed devices are only 10 or 100-base-T (sub gigabit) devices as they only use 4 wires. Gigabit devices require use of all 8 wires so it doesn't work for 1000-base-T devices. Also, if the RJ-11 cable is flat-wire (not twisted pair UTP) then the run will have to be very short due to noise considerations. This makes it harder to achieve full speed on 100 Megabit class connections.