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Reviews Categories | Packet TNCs | MFJ 1270C TNC Help

Reviews Summary for MFJ 1270C TNC
MFJ 1270C TNC Reviews: 8 Average rating: 4.9/5 MSRP: $130
Description: VHF/HF Packet TNC. Connects to a PC serial port and your radio.
Product is in production.
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K9CTB Rating: 5/5 Sep 29, 2007 00:42 Send this review to a friend
Great workhorse TNC!  Time owned: more than 12 months
I received a 1270C as a gift, and thought I'd write a review here. A fellow ham in my home state of Indiana gave (yes, there are those who still do that) me the 1270 and a mic/TNC switching box a few years ago. It was planned to get me up on VHF with a store-and-forward BBS system.

The 1270 is a great little box. It's just a clone of the TAPR TNC-2 from way back ... with a switchable HF/VHF modem and MFJ's version of the controller firmware -- with a PBBS and 32K of RAM.

Some say packet radio is dead, and I won't go into that here. The 1270 is still a very desirable shack item and you can verify this by watching the used gear ads or e-bay.

My 1270 is connected to an Icom IC-207H as a VHF node, and I use an older, standard firmware set so as to be compatible with the MSYS DOS BBS software, which requires operation in the KISS mode.

Absolutely no complaints about this gem. It has worked flawlessly 24/7/365 for about 3 years now. Originally, there was concern that over a period of extended use, these TNC-2 clones (MFJ included) would actually take themselves out of the KISS mode and simply stand idle without responding to the software. I have never noticed this at my station, but there are some software-savvy folks in the HF packet group who developed a routine to occasionally send the TNC a "go into the KISS mode" command, just in case. If it ever did pop out of KISS, the command would put it back in line.

I think if they're kept clean and not thrown around the shack, these boxes can last forever! Batteries are easily replaced, and they are simple to connect to your rig. If you want to play with packet and you see one of these, pick it up and give it a try.
OE3SGU Rating: 5/5 Oct 1, 2006 13:22 Send this review to a friend
Good workhorse  Time owned: more than 12 months
I had the B model for many troublefree years and it did a great job without any problems at all.
NU0C Rating: 4/5 Aug 22, 2006 19:21 Send this review to a friend
Good hardware, but with bugs  Time owned: more than 12 months
I've had MFJ TNCs since my first 1274 in the mid 1980s. I acquired this 1270C used several years ago, and it has been running my APRS digi for close to 6 years with minimal problems. As for the bugs...

When I first picked it up, I benched it to do calibration and noticed electrolytic capacitor C75 looked a little bulged. C75 is not shown on any schematic I have found, but it is connected directly to the +5V rail. It is a 470 uF 16V part near the back of the unit. I confirmed with a voltmeter that C75 was installed backwards, but was correctly polarized according to the board silkscreen. This is 1270C/1274C/1276 PCB Rev. 11, board number 35-550-10. Better check yours, this may be the reason some have reported poor operation with the current limited wall wart supplies. Best case, no damage will occur from the backwards cap; worst case, the cap could leak and damage the circuit board, or an overhearted wall wart could start a fire! Again, the silkscreen markings for C75 are WRONG, you will need to pull the board and verify polarity with an ohmmeter. Two 1274 models I have are correct. I emailed MFJ with a note about this problem and got NO response, so they get a 0 for support.

The unit drifted out of cal last year, and I couldn't get the cal routines in the manual to work as described. I had to use a combination of methods from and various TNC-2 sources. MFJ has done some tinkering with the design, and some of the cal jumpers do not seem to do what they are supposed to.

The good news about the design tinkering is that MFJ seems to have implemented a version of the N7OO DCD mod that is published on the internet.

In short, good hardware with some quirks, not for the "appliance operator" if there are problems. Supports most standard TNC-2 firmware, and easily repairable with off-the-shelf parts. Very reliable when properly tweaked. MFJ support is questionable.
KC4IVG Rating: 5/5 Jun 18, 2003 22:14 Send this review to a friend
KISS?....NOT!  Time owned: 0 to 3 months
The MFJ-1270C is a great little TNC.....BUT!

The new ones coming out since MAY 03 dont have "KISS"...Theres no command to turn it on or off even though its listed in the commands in the manual. It doesent even come up when you issue the DISPLAY command...Its not there anymore!!

Its advertised that it does in the latest ads everywhere but I had to get a different version (OLD VERSION)of the chip from MFJ (20$ plus shipping if you have to pay for it) but they are getting ready to change their advertising and not mention KISS mode.

If you need KISS.....Avoid it unless your going to buy another chip.

By the way its not a silver faced TNC anymore. MFJ has changed to a black face that matches more of the modern radio equipment...Very nice!
KB9WWL Rating: 5/5 Jan 9, 2002 20:54 Send this review to a friend
Excellent!  Time owned: 0 to 3 months
I use the 2400-baud version of this TNC with the 1272B switchbox (doesn't have adequate shielding!!) for my local BBS/iGate, DX Cluster, and APRS. It works wonderfully! Also like the built-in mailbox system.

The one problem I had: It took me 2 days to figure out how to get it to transmit with my quirky radio!!

If you're looking for a TNC, don't hesitate to buy this one!

73 Ben, KB9WWL
KD7NCS Rating: 5/5 Oct 10, 2001 12:34 Send this review to a friend
Easy and reliable  Time owned: 0 to 3 months
I'm brand new to packet, and was looking for the "standard" TNC that was most commonly used. I purchased this unit at Radio Shack under the Vectronics label (the documentation was MFJ). It took some experimenting to get the settings right, as the documentation is a little weak and I'm so new. I would highly recommend WB9LOZ's website at for a great primer on packet radio. All the information you need to get started is there.

The most important problem I found was that the power supply that comes with the TNC is worthless (it's one of those little transformers that plugs into the wall). It introduces a terrible 60hz hum into the modulation that make the output signal almost usless. Cut the cable off the the power supply and throw the transformer away. Make sure you have the polarity straight on the cable and connect it to a decent regulated 12v DC supply or you shack battery.

Once is was set up, logging on to the local nodes was a piece of cake! I did find that you have to set the MYCALL parameter in the command mode, or the nodes will not log you on. Apparently, terminal software doesn't do this automatically (at least in my case). I have it connected to my Yeasu FT-1500. Making the cable for it was straightforward--If I could do it anybody could!

There is a 'Starter Pack' available for this unit. I can't recommend it as all it contains is a simple terminal program and a 25 pin RS 232 interface cable for the com port on your computer. You can make or purchase the correct cable yourself, and download a free terminal program for much less than the starter pack costs.

This is a great way to start out in packet. I purchased this after a bad experience with a Kantronics product that quit after about a day and a half.
KA2UUP Rating: 5/5 Aug 15, 2001 09:18 Send this review to a friend
Great for dx cluster and bbs work  Time owned: 0 to 3 months
I am somewhat new to packet. However I was surprised at the simple hook up required. The unit orignally was sent to me by MFJ after I requested a replacement under warranty for a 1214PC unit. Since they forgot about my order, they admitted to their mistake and were generous enough to put in the 2400 baud modem in it. Only concern was that they sent the wrong power converter (240V 50 hz instead of 110V 60 Hz), but I had the right one at home. I started using BuxTerm (DOS) since I had the software at home. The Windows software from MFJ is far superior. I have a laptop for my packet work and it does a great job. I specially like the automated functions for signal reports submission. I have not tried it in HF so I cannot report on that, yet!
K8AC Rating: 5/5 Oct 24, 2000 18:22 Send this review to a friend
Excellent TNC for DX Packet Cluster  Time owned: 0 to 3 months
I use the 1270C only to connect a 2 mtr. rig to my PC to monitor a DX Packet Cluster station. It's perfect for that application - low price and works out of the box with very little setup. Available for $119.95 from AES. You must supply the serial port cable (25 PIN at 1270C end), and a connector for the radio end of the interface cable (1270 to radio). If you're going to use this TNC for regular packet operation, consider buying one of the Starter Packs ($24.95) which includes the serial cable and PC packet software. Only one criticism of this unit: it's very deep considering the overall size. You'll need about 11" of shelf depth to accomodate the unit and the interface cable connectors. Can be easily stacked with other equipment as it has no vents in the cabinet, and is pretty solid. Documentation supplied includes a "Fast Start" manual and an "Instruction" manual of about 290 pages, including schematics. I had one minor operational problem at first, but a quick call to MFJ support provided the necessary info to set the options correctly for my application.

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