What does "265 DPL" mean as a repeater Input Tone?

[RogerSpendlove]

A repeater I'm wanting to connect to is listed as having Input Tone "265 DPL," but this doesn't match any of the options in my Radiodity GM-30 (actually a Baifeng GM-15) software. The options I see are "D265N" and "D264I." Which one should I use? And should I enter this my my transceiver's Rx DCS or its Rx CTCSS?

[StogieVol]

7 minutes ago, RogerSpendlove said:

A repeater I'm wanting to connect to is listed as having Input Tone "265 DPL," but this doesn't match any of the options in my Radiodity GM-30 (actually a Baifeng GM-15) software. The options I see are "D265N" and "D264I." Which one should I use? And should I enter this my my transceiver's Rx DCS or its Rx CTCSS?

The DPL just means digital, So what you want is that D265N for your tone. And that was a good question. Feel free to ask anything. 

[Guest]

57 minutes ago, RogerSpendlove said:

A repeater I'm wanting to connect to is listed as having Input Tone "265 DPL," but this doesn't match any of the options in my Radiodity GM-30 (actually a Baifeng GM-15) software. The options I see are "D265N" and "D264I." Which one should I use? And should I enter this my my transceiver's Rx DCS or its Rx CTCSS?

N is normal I is inverted.   In gmrs is should always be N unless some one is not playing by the rules. 

[OffRoaderX]

1 hour ago, Socalgmrs said:

In gmrs is should always be N unless some one is not playing by the rules. 

Thanks for trying, but this is incorrect.  GMRS/the FCC rules fully support "i" or inverted DCS/DTC/DPL tones. 

In a case where N or "i" is not specified, it can always be assumed to be "N" (Normal).

[WRUU653]

59 minutes ago, Socalgmrs said:

N is normal I is inverted.   In gmrs is should always be N unless some one is not playing by the rules. 

What rule is that? Rhetorical question. There is no rule you can't use inverted for GMRS. 

[WRUU653]

@OffRoaderX you be fast sir 

 

[RogerSpendlove]

Thank you for answering! Do you happen to know what is the difference between the 'N' and the 'I' options?  I see both in the programming software, but in the transceiver itself, only the N options appear.

[RogerSpendlove]

Never mind! I didn't see Socalgmrs's reply above!

[marcspaz]

1 hour ago, RogerSpendlove said:

Thank you for answering! Do you happen to know what is the difference between the 'N' and the 'I' options?  I see both in the programming software, but in the transceiver itself, only the N options appear.

 

DCS / DPL uses a binary code to decide if the squelch opens or not.  In standard DCS (Normal, or N), they use frequency shift keying, with a negative frequency shift being equal to zero and a positive frequency shift being equal to one.

 

Manufactures can opt to reverse (Invert, or I), the meaning of the frequency shift.  Meaning the negative frequency shift can equal one, and a positive shift can equal zero. 

There is no way to automatically detect this, because the encode/decode process is based in time and time-shifting.  So, you have to manually configure the radio to define if you are you using Normal or Inverted.

[WRHS218]

13 hours ago, RogerSpendlove said:

And should I enter this my my transceiver's Rx DCS or its Rx CTCSS?

You would use the DPL in the Rx DCS.

[dosw]

DPL = Digital Private Line, which is a totally misleading name for DCS (Digital Coded Squelch). It is very similar to the also poorly named "PL" tones (Private Line, which they aren't), which are just CTCSS tones (Continuous Tone-Coded Squelcy System) tones.

 

DCS and CTCSS are a way of layering in information to your transmissions that allows a receiving radio to hear that information and open squelch so the receiving party can hear you, and only hear people transmitting with the same tone. It works like this:

Transmitting radio transmits your voice, and also a continuous "Tx tone". Receiving radio hears there is something being transmitted on the frequency. If it has an Rx tone set, it will only turn on its speaker and play what it's receiving if the Rx tone it has set is the same as the Tx tone you're transmitting. It would also turn on the speaker if it has NO Rx tone set. The Rx tone is an opt-in tool that the receiving user can set so that they don't hear everything that comes on a frequency, only those things that are accompanied with the correct tone.

The tone, if it is CTCSS, is an actual sine wave tone in the lower audio-frequency range within the transmission. It will sound like a hum at a specific frequency; 123.5, for example means 123.5Hz. A DCS tone is a digital code transmitted along with the voice transmission, also in a lower audio-frequency range within the transmission. It will sound like a low-frequency buzz. Receiving radios apply a high-pass filter (low-reject filter) to make it so that you, the listener, don't actually hear the tone or code.

If you were to listen through an SDR with the filter setting disabled, you would hear it. It's mildly annoying.

 

Within DCS, N is normal, I is inverted, as has already been stated in this thread. And when the "N" isn't specified, it's implicit. Normal might mean you are transmitting 1010, and inverted would mean you're transmitting 0101. Unfortunately there are collisions, so N vs I doesn't mean a doubling of the number of possible encodings, but it does produce more than if you didn't have the option of inverting. 265, for example, may be 100001001. That would be the "N" encoding. If it were inverted (I) encoding, it would be 100100001 that gets transmitted.

In reality it's not *quite* that simple of a protocol. The bit patterns contain parity bits, "always" bits, and the three-digit code, bits. https://mmi-comm.tripod.com/dcs.html . The patterns are 23 bits.

 

[RogerSpendlove]

Thank you all for your responses! They've been most helpful. I'm traveling to / camping in the area of this repeater this weekend, so I'll get to find out if I've programmed my HTs properly. But if not, you'all have armed me with the understanding to probably correct it!