Tnc sound cards

[W8MSD]

I have noticed that Timewave Technology offers the PK-232 sc, DSP-232 Plus and an upgrade for the PK-900 with a sound card option.

Is there a difference between the TNC sound card options and the Signalink USB soundcard? Thanks in advance.

[W8JX]

Well with a PK232 with a sound card upgrade you would still have positive PTT control vs a USB signal link only has internal VOX PTT control with is not quick enough for some modes.

[AA4PB]

I think that the PK232 sound card upgrade is really just an audio interface that couples your computer sound card to your radio via a couple of transformers. The SignaLink-USB, on the other hand, contains its own internal sound card and does not use the computer sound card at all.

The SignaLink-USB does use a VOX-like circuit to detect the audio tones and key the PTT circuit in response. On the plus side, it doesn't require a serial port on the computer to control the PTT. It may be too slow for some of the new fast-switching modes but I've not had any problems with PSK31 or any of the normal keyboard-to-keyboard text modes.

Unless you really want the PK232's TNC for Pactor or some other ARQ mode that you can't run through a sound card, I'd go with the SignaLink-USB.

[W8JX]

Unless you really want the PK232's TNC for Pactor or some other ARQ mode that you can't run through a sound card, I'd go with the SignaLink-USB.

I use  a Rig Blaster Plug N Play and a 10 dollar USB plug in sound card. I have a separate sound card and full PTT control via its USB interface.

[STAYVERTICAL]

I have used a USB signalink with ALE400, its not pretty but it works...slowly.
Unless you are a big packet user, stick with the USB signalink, you can always make a simple PTT circuit from a Serial port for a few dollars, and a couple of cheap audio transformers will do the audio line isolation.

73s

[W8JX]

I have used a USB signalink with ALE400, its not pretty but it works...slowly.
Unless you are a big packet user, stick with the USB signalink, you can always make a simple PTT circuit from a Serial port for a few dollars, and a couple of cheap audio transformers will do the audio line isolation.

Or you can use P-n-P to begin with and not have to worry about rigging up a PTT control line later. It truly is plug and play.

[NA4IT]

While the Timewave thing was a good idea, it was dependent on software writers to include the "ModemSwitch" software in theirs, which I think the only one that did was MixW (please correct if I am wrong, there may also be a for pay software that does it).

All the above said, here is what happens with one of the sound card equipped units in use...
1) Run ModemSwitch to switch TNC to sound card use
2) Open digital software
3) When ready to TX, switch back to ModemSwitch and click TX, switch to digital software and type, switch back to ModemSwitch to unkey.

So form your own opinion. My preference would be a Signalink USB instead of the sound card upgrade to the TNC. Then build a switch to switch them in and out, or put the PTT lines together through a small signal diode on each line, and the TX Audio through a 100K resistor on each line. Tie the RX lines together, and you got it.

[W8JX]

The TNC can do FSK keying which is a plus if you do RTTY or pactor or packet and your rig supports FSK. Signal link does not and again a VOX PTT is far for ideal at times. It is a shame that they did not spend a few more bucks and a little more time and add positive PTT control option to it.

[STAYVERTICAL]

The TNC can do FSK keying which is a plus if you do RTTY or pactor or packet and your rig supports FSK. Signal link does not and again a VOX PTT is far for ideal at times. It is a shame that they did not spend a few more bucks and a little more time and add positive PTT control option to it.

When I made up my P.T.T. and C.W. interface using RTS and DTR signals, I used another optoisolator (4N25 chips - very cheap) on the TXD line.
This gives an optoisolated keying line for true FSK keying, although it may be necessary to add higher power transistors if you are using an older rig. The whole thing is tiny and in "dongle" form.
Very cheap, and gives you optoisolated PTT, CW and FSK for a total cost of about 9 dollars.
Sometimes, doing one thing well is better than multiple things poorly.

Just a thought.

73s

[W8JX]

Sometimes, doing one thing well is better than multiple things poorly.

Well in case of Signal Link USB I would not say well done...

[W8MSD]

Appreciate all of the responses. It would appear that the best system for VHF/HF Packet is the old school TNC, I have tried Signalink USB W/MixW with good results, but no mailbox that I am aware of.

I have purchased a DSP-232 plus that I have sent to Timewave Technology for the USB port install. I will investigate the internal sound card when it returns.

[NA4IT]

Trust me, use the Signalink USB for sound card modes, the TNC for packet modes. In fact, there is so little packet on HF, I would suggest a standalone setup on VHF using the TNC and something like a Alinco DR135 or Motorola GM300, and use your HF rig and SLUSB for HF digital.

[W8MSD]

Thanks, I have both and will keep both units. Great input...

[NA4IT]

I also have a page of tips for running the SLUSB, including both a switch for it and a TNC, and a schematic showing how to hook both to your radio. See http://www.qsl.net/na4it/slusb/slusb.html.