Modem problem -- help, please!

Has anyone here had any experience in using a modem on a VoIP line? I know that's a bit backwards, but that's what I'm dealing with now... I seem to be having some problems with line noise on my Commodore, and I've been told it's because of the VoIP line, but I'm not entirely convinced that that's the case. First of all, my VoIP line #2, which I have set up for the BBS only, is configured with "Fax and Modem Support" turned on. With that on, the documentation states:

If you turn Fax and Modem Support on, a portion of your available data bandwidth will be reserved exclusively for data support.

It goes on to say:
Fax and Modem Support works with most commonly used fax machines as well as some other data services, including
- analog modems, including those embedded in consumer electronic devices
- personal video recorders (such as TiVO)

So according to this, with this "mode" enabled, it *should* work just fine.

Okay, second point... I've hooked up my laptop with built-in modem to the same line, called out to a BBS, and I don't seem to get any line noise at all... And the modem in my laptop is 56K bps, compared to the 1200 baud in my Commodore, so if there was a line noise problem, wouldn't it be significantly worse at the higher speed?

And third point... I only tested the modem briefly on a traditional line before switching to VoIP, but I think I was having some line noise issues before the switch.

So... with all these points put together, it seems to me that the problem is not with the line at all, but rather with the modem. So would getting a new modem help? Any thoughts?

-Andrew

At some point, the modem guys came along with "error correction". I have been "modeming" since accoustic coupler days. Likely need a modem that supports MNP 5 or v.42bis. (oh, stop being impressed, I just googled all that stuff because I couldn't remember any of it either).

When it connects, I get a "1200 NoEC" connect string, meaning No Error Correction. I live where the phone lines are very poor quality (100 miles north of Las Vegas NV in the middle of nowhere). I'm sure that's why it's hopeless without error correction for me to try it.

Even calling locally, the best I can usually do, even with 56k modems, is 26.4k. Rarely I'll get a 28.8k connect and every 2 years I'll get a 31k connect once.

Chuck,
Thanks for your helpful tips... I'll do some searching around for a compatible modem... Hey... maybe I'll "upgrade" to 2400 baud through all this... ;-)

I don't have a VoIP line. However ...

Internet telephony relies on data compression and packetizing the data. So you have two potential problems - the data compression that they are using is 'doing a number' on the analog tones coming from the modem, and you may be experiencing dropped packets on the network connection. Both are bad. The 'Fax and Modem' support might address both problems. Definitely use it.

If your modern laptop can run a modem at 53.3Kbp/s on that line, then the line is probably good enough. I would test the Commodore modem on a real analog line.

The Commodore modem is around 20 years old. It could be suffering from old age. Capacitors deteriorate, filtering components age, etc. Make sure the things you can control like the phone wires and connections to the computer are good and possibly look for another modem to test with.

One thing working in your favor is that the old modems are fairly low-tech and were probably built pretty well. 1200 bps is not stressful for any phone line, unless you are in a third world country. Old timers will tell you stories about being able to make noises into a handset on 110 and 300 bps modems to generate characters. There is a lot of room for slop there.

mbbrutman said:

The Commodore modem is around 20 years old. It could be suffering from old age. Capacitors deteriorate, filtering components age, etc. Make sure the things you can control like the phone wires and connections to the computer are good and possibly look for another modem to test with.

Click to expand...

That's exactly what I was thinking... I was just looking for some outside confirmation. ;-)

I'm going to do some eBay hunting for a replacement modem (or two) that I can use to do some troubleshooting with.

mbbrutman said:

One thing working in your favor is that the old modems are fairly low-tech and were probably built pretty well. 1200 bps is not stressful for any phone line, unless you are in a third world country. Old timers will tell you stories about being able to make noises into a handset on 110 and 300 bps modems to generate characters. There is a lot of room for slop there.

Click to expand...

I still remember when I upgraded from 300 to 1200 baud and thinking, "Now I have a FAST connection!" Nowadays, after using Cable Internet, going back to a 56kbps dial-up connection seems slow. Of course, most of that is due to how loaded down with high quality graphics everything is. Back in the days when I shifted up to 1200 baud, it was all mostly text...

-Andrew

I had used 110 and 300 bps modems on other systems, but my first modem was a Hayes 1200. That was the gold standard at the time, and it commanded a comensurate amount.

The upgrade to 2400 was great, and then after that the upgrade to 14.4 was mind blowing. In between that time all sorts of features such as compression and error corrrection started slipping in.

After getting a cable modem in the house 6 years ago I've not used a modem more than once or twice a year, while I'm on the road for business.

I like what you are doing with the authentic BBS, but have you considered Ethernet? I thought there were Ethernet adapters (semi-homebrew) that you could use to put the C64 on the network. I guess that after you cram TCP/IP in there that there would not be much left for the BBS software.

Another issue that you might consider for the longer term is using a null modem cable between the C64 and a Linux machine, and having the Linux machine do the work to make the C64 available on the network. The C64 (with a serial port and null modem cable) would still think that it was accepting telephone calls, and the Linux box would handle telnet connections and repackage the data from the null modem cable. That would give you the feel of an authentic C64 BBS, but available via telnet.

mbbrutman said:

I like what you are doing with the authentic BBS, but have you considered Ethernet? I thought there were Ethernet adapters (semi-homebrew) that you could use to put the C64 on the network. I guess that after you cram TCP/IP in there that there would not be much left for the BBS software.

Another issue that you might consider for the longer term is using a null modem cable between the C64 and a Linux machine, and having the Linux machine do the work to make the C64 available on the network. The C64 (with a serial port and null modem cable) would still think that it was accepting telephone calls, and the Linux box would handle telnet connections and repackage the data from the null modem cable. That would give you the feel of an authentic C64 BBS, but available via telnet.

Click to expand...

Yes, I did consider that... But there are already several Telnet-accessible Commodore BBS's out there, and what I'm really trying to do is to preserve the "lost art" of the dial-up BBS. Not only that, but I'm providing a service to anyone out there that wants to test out their old modem on something.

-Andrew

VoIP may or may not support modem calls. You need a decent modem to get away with it.

Some providers like Vonage require a *99 code to be inserted before the number to maximize quality (and maximize bandwidth usage). You should also make sure that if you don't have this type of option, that you ensure that you have the VoIP service configured to give the highest possible quality (i.e. use maximum bandwidth).

With my Courier V.Everything modems I can get >50kbps connections over Vonage and Primus Canada. I have trouble using my 1200 bps Commodore 1670 though; no luck yet with that.