In general - yes.
which card you cisco have? it is a serial E1/T1 interface card or async card with modem attached or Cisco 1-Port Analog-Modem Interface Card?

for analog modems you need a pbx with phone line, ring tone / call /etc features. max speed is 33.6k

for e1/t1 you need a pbx with e1/t1 and analog ports. max speed 56k.

so it's possible but a bit complex.

I have seen a Youtube video of two PCs dialed up with modems, and all that was needed was IIRC a 9V battery and a resistor. Modems won't pick up a line, or start dialing, something like that, without some electricity on the phone line.

56K was a maximum theoretical download, by default they had 33.6K upload. So modem to modem was 33.6K, and in the dial up internet days the modem terminated on the phone company's kit and traffic routed then to the ISP digitally (so up to 56K was possible, though 56K itself was basically theoretical). There are initialisation strings for v.90 or v.92 that can trade some downstream for upstream, and perhaps a 44K ish link is possible?

GL

edit: Was this vid https://www.youtube.com/watch?v=luarFqislIc

dm- wrote on 2023-09-27, 10:54:

In general - yes. which card you cisco have? it is a serial E1/T1 interface card or async card with modem attached or Cisco 1-Po […]
Show full quote

In general - yes.
which card you cisco have? it is a serial E1/T1 interface card or async card with modem attached or Cisco 1-Port Analog-Modem Interface Card?

for analog modems you need a pbx with phone line, ring tone / call /etc features. max speed is 33.6k

for e1/t1 you need a pbx with e1/t1 and analog ports. max speed 56k.

so it's possible but a bit complex.

The board in the cisco is this WIC-1AM https://www.cisco.com/c/en/us/support/docs/ro … 57-wic-2am.html

The problem is setting up and finding a PBX 😅

progman.exe wrote on 2023-09-27, 12:09:

I have seen a Youtube video of two PCs dialed up with modems, and all that was needed was IIRC a 9V battery and a resistor. Mode […]
Show full quote

I have seen a Youtube video of two PCs dialed up with modems, and all that was needed was IIRC a 9V battery and a resistor. Modems won't pick up a line, or start dialing, something like that, without some electricity on the phone line.

56K was a maximum theoretical download, by default they had 33.6K upload. So modem to modem was 33.6K, and in the dial up internet days the modem terminated on the phone company's kit and traffic routed then to the ISP digitally (so up to 56K was possible, though 56K itself was basically theoretical). There are initialisation strings for v.90 or v.92 that can trade some downstream for upstream, and perhaps a 44K ish link is possible?

GL

edit: Was this vid https://www.youtube.com/watch?v=luarFqislIc

I'll look at it later

If you just want to be able to make one modem call another one, buy one of these no PBX needed

if you need the dialing then you need a pbx, if you just want to make a connection, tell one to ignore the dialtone ATX0 and dial out ATD and the other to respond ATA.

oh yeah and do connect both of them together with a telephone cable. 😀

weedeewee wrote on 2023-09-27, 15:47:

if you need the dialing then you need a pbx, if you just want to make a connection, tell one to ignore the dialtone ATX0 and dial out ATD and the other to respond ATA.

oh yeah and do connect both of them together with a telephone cable. 😀

This seems like the right way to me. I just have to figure out how to do it with the Cisco.
But the 9V battery and resistor then are not needed if I tell the modem to ignore dial tone?

I know, just pointing at YT is the most contemporary of internet answer 😀

Of course the vid I linked to has the obligatory poor production values[1]. But the camera is static, and the video is edited, which is great as far a YT goes 😀 I linked to it because I think it will actually give you some ideal pointers.

A bit more seriously, it has some wiring diagrams, and he does explicitly show a plain cable will not work. A resistor and non-new 9V battery, to give ~20mA is how he tricks the modems into connecting.

[1] I have put ~3 vids ever on there, and so I know just how bad things are.

matti157 wrote on 2023-09-27, 17:09:

weedeewee wrote on 2023-09-27, 15:47:

if you need the dialing then you need a pbx, if you just want to make a connection, tell one to ignore the dialtone ATX0 and dial out ATD and the other to respond ATA.

oh yeah and do connect both of them together with a telephone cable. 😀

This seems like the right way to me. I just have to figure out how to do it with the Cisco.
But the 9V battery and resistor then are not needed if I tell the modem to ignore dial tone?

I'm fairly certain the resistor & battery are not needed, though never tried it myself... I think. can't recall. it's been like 25 years since I last used a telephone modem.
also the 9v & resistor won't a dial tone make.
I'd say try it. If it doesn't work you can go for the battery & resistor.

If you have a second modem, ie not the cisco, that would make an easy setup.
Setting up the cisco might be the hardest part, though I have no knowledge nor experience with cisco configurations.

edit: funily enough, today someone on tweakers.net is selling two cisco 1841 without modeminterface.

I didn't need a resistor and a battery when I did this myself maybe 30 years ago for a surprisingly functional network to play Doom.

You can also use UniPCemu's server build with it's special nullmodem cable: UniPCemu manual.
Under extra features, there's a link for the UniPCemu Hayes nullmodem cable.

If using that nullmodem cable (and either a terminator on the client's end or another serial port that's unused) you can have UniPCemu behave as a serial modem, providing the same kind of service as the WiFi232 modem, but it includes a dial-up ISP server as well (if (Win)pcap is installed). It can dial IP addresses (ports with :<portnumber> suffix) when specifying 9 digits (example 127000000001 for loopback adapter (127.0.0.1) default), but also can dial normal webaddresses (for example "google.com:80" to connect to google's HTTP service using TCP). Since it's also running a ISP packet server if pcap is installed and enabled by specifying the ethernetcard setting, it can also dial itself (it's own IP or 127.0.0.1 loopback address) to provide internet access using PPP (IPv4 and/or IPX) or SLIP (and a handful of other packet types as well when using text-based authentication). If no packet server is enabled (ethernetcard setting being -1), dialing it's own configured port will make the modem ring and answer the call instead (so other clients like Dosbox or even another UniPCemu modem can dial it).
So using two of those UniPCemu serial Hayes modems (requires 2 serial ports (required for full Hayes modem) for each UniPCemu modem) you can connect two normal computers with dial-up together over either a normal dialling configuration (by dialing without packet server enabled on the receiving side) or dial UniPCemu's packet server IP to get full internet/ethernet access (and even communicate to each other using either IPv4 or IPX).