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I have a very old laptop I use as a home server and it has an RJ11 port. Apart from calling through and from with this connection as a landline, are there any other practical uses for this today?
Erik
Posted 2019-11-04T20:38:19.947
Reputation: 141
2
That RJ-11 port almost certainly is just a POTS modem (Plain Old Telephone Service; analog dial-up voice landline modem).
Without a real telephone landline, and perhaps even without a simulator box that provides dial tone and ring voltage and DTMF touchtone decoding, you could probably hook it directly to another POTS modem via a telephone line cord (RJ-11 cord) and make a 33.6 kilobit per second (or less) connection over it, if you have a good serial comms app/tool and know your Hayes AT command set.
Spiff
Posted 2019-11-04T20:38:19.947
Reputation: 84 656
2As @Spiff states, you can set up a 56 kB "network"... and have done so back in he days of the Atari 800XL and Apple IIe. A ring tone wasn't required, and a 24 VDC wallwart with 600 ohm resistor provided bias (actually, 14 kbS, for those modems). – DrMoishe Pippik – 2019-11-04T21:28:47.360
@DrMoishePippik Hah! I'm a bit too young for those days, but I might want to try that out sometime. – Erik – 2019-11-05T00:15:07.640
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RJ-11 jacks have one other use: Receiving and transmitting faxes.
Yes, faxing is 19th Century tech, but many doctors' offices and real estate firms still rely on it. Note: Faxing from a PC works best over a Plain Old Telephone Service ('POTS') line, will interfere with DSL service, and fails often if you your phone service is delivered over a digital carrier line.
K7AAY
Posted 2019-11-04T20:38:19.947
Reputation: 6 962
That port will have special hardware behind it in your laptop. If it is a 56k modem then you will be limited to the things a 56k modem can do: being a modem and (maybe) making phone calls. – Mokubai – 2019-11-04T23:13:41.880
@Mokubai Cool, I'll look into it. I might use it to record my phone conversations. – Erik – 2019-11-05T00:18:25.873