DSDPlus Complete Guide

                    v2.547 • PUBLIC RELEASE • FAST LANE
                

Digital Speech Decoder Plus

The ultimate interactive guide to decoding P25, DMR, NXDN, D-Star, and more. From single-conventional monitoring to complex multi-site trunk tracking.

📥 Installation & Setup

1. Initial Setup

Create Folder

Create C:\DSDPlus (do not use existing 1.101 folder)

Download Base Files

Get DSDPlusFull.zip from dsdplus.com

Extract all files to C:\DSDPlus

Missing Files?

If programs report missing files:

Download DSDPlusBaseFiles.zip
Copy all EXE and DLL files to DSD+ folder

2. SDR Hardware Setup

🔌

RTL-SDR Dongle

RTL2832U-based • Budget option

Use FMP24

📡

Airspy Mini/R2

Higher performance • 10/12-bit ADC

Use FMPA

📻

SDRplay RSP2

14-bit ADC • API 3.11

Use FMPP

Configuration File:

Required DLL Files

FFTW3

Spectrum processing

libfftw3f-3.dll

From: fftw-3.3.5-dll32.zip

RTL-SDR V4

RTL-SDR Blog v4 support

rtlsdr_V4.dll

In FMP24 folder

SDRplay API

RSP2 support

sdrplay_api.dll (v3.11)

In FMPP folder

〰️ Supported Protocols

Click any protocol card to see detailed decoding capabilities and configuration requirements.

🏢

PUBLIC SAFETY

P25 (Phase I/II)

Project 25 trunked systems used by police, fire, EMS.

Phase I IMBE Phase II TDMA 9600/12000 CC

💼

COMMERCIAL

DMR/MotoTRBO

Digital Mobile Radio including Capacity+, Connect+, Tier III.

Cap+ Con+ Tier III Std/NonStd

📻

NEXEDGE

NXDN / NEXEDGE

Kenwood/Icom systems with 4800/9600 bps variants.

4800 bps 9600 bps iDAS

🎙️

AMATEUR

D-Star

Digital Smart Technologies for Amateur Radio.

GPS Messages Text Messages Routing

📡

YAESU

Yaesu Fusion

C4FM modulation with half/full rate voice.

Full Rate IMBE Half Rate AMBE+2

🛡️

EF JOHNSON

ProVoice

EF Johnson legacy IMBE voice synthesis.

IMBE Simplex/Inbound

🌐 Trunk Tracking Modes

💻

Single Receiver

One SDR device switches between control channel and voice calls. Uses TCP link exclusively.

Batch File: 1R.bat

Parameter: -r1

FMP Command: -i1 -o20001

🥞

Dual Receiver

Dedicated CC and VC receivers for prioritized voice following. Best performance for all system types.

CC Batch: CC.bat (-rc)

VC Batch: VC.bat (-rv)

Hardware: 2x SDR

📄 Configuration Files

Network Definitions

Define trunking systems by protocol, ID, and alias.

Required for Trunking

; Format: Protocol, NetworkID, "Alias" [, options]
P25, BEE00.1D9, "Palmetto 800"
Con+, 1234, "ACME Inc"
NEXEDGE96, 13, "City Services"
TIIIStd, L13, "Regional Net"
TIIInonStd, L1234:13, "Road Runner"
Cap+, 9999, "Mayberry PD"
; TIII with CPS-P3 numbering:
TIIIStd, L13, "Coyote LLC", CPS-P3

P25: WACN.SysID format (hex.hex)

DMR: Decimal system ID

TIII: Add model prefix (T/S/L/H) + optional network prefix (1-4095)

Cap+: Assign unique NID (use RR DB page number)

Site Definitions

Define individual sites within networks.

; Format: Protocol, NetworkID, SiteID, "Alias"
P25, BEE00.1D9, 1.1, "North Site"
P25, BEE00.1D9, 1.2, "South Site"
Con+, 1234, 1, "Site 1"
TIIIStd, L13, 1.1, "HQ"
TIIInonStd, L1234:13, 1, "Home Base"
NEXEDGE96, 13, 1, "Downtown"

Site Number Formats:
P25: RFSS.Site (e.g., 1.1)
TIIIStd: Area.Site (e.g., 1.1)
TIIInonStd: Site only (e.g., 1)
DMR: Decimal site number

Channel Frequencies

Map channel numbers to frequencies for trunk tracking.

; Format: Protocol, NetID, Site, Chan, TX Freq, RX Freq, Sort [, DCC]
P25, BEE00.1D9, 1.1, 1, 853.9875, 808.9875, 0
Con+, 1234, 1, 1, 451.3125, 456.3125, 0, 12
Cap+, 9999, 1, 1, 450.5000, 455.5000, 0
TIIIStd, L13, 1.1, 1, 454.7000, 0.0, 0
; Unknown values:
Con+, 123, 1, ?, 454.6125, 0.0, 0
Con+, 123, 1, 7, ???.????, 0.0, 0

Cap+ Setup Tip: Initially use invalid channel numbers (99) until DSD+ determines correct ordering (e.g., "450.500 is first Cap+ repeater (Ch1 and Ch2)"), then update with correct channel numbers.

DCC Field: Optional Digital Color Code for DMR disambiguation when multiple sites share frequencies.

Talkgroup Definitions

Auto-populated but editable for aliases and priorities.

; Format: Protocol, NetID, GroupID, Priority, "Alias"
P25, BEE00.1D9, 1001, 50, "Dispatch North"
Con+, 1234, 100, 10, "Security"

Lower priority numbers = higher priority (1-99). Use HIGH or HOLD for must-monitor groups.

TDMA Tagging: Enable in menus to append " (TDMA)" to talkgroup names for Phase II systems.

Radio ID Definitions

Individual radio identifiers with optional aliases.

; Format: Protocol, NetID, RadioID, "Alias"
P25, BEE00.1D9, 100001, "Unit 101"
DMR, 1234, 1001, "*Dispatcher"
; Prefix meanings:
DMR, 1234, 1002, "~Partial" ; ~ = partially unscrambled

* (Asterisk): OTA (Over-The-Air) alias from system

~ (Tilde): Partially unscrambled Motorola alias

Backup Recommended: Version 2.516+ changed radio file format. Backup DSDPlus.radios before updating - Motorola talker alias data may be discarded during update.

Site Loader

Quick access list for tuning to sites or conventional channels. Press L in DSD+ to open.

; Trunked entries (Site 0 = network header):
P25, BEE00.1D9, 0, "Palmetto 800"
P25, BEE00.1D9, 1.1, "North Site"
; Conventional entries (Freq first, then mode):
Conv, 1, 1, "162.550 WX1"
Conv, 1, 2, "119.150 AM ATIS"
Conv, 1, 3, "163.830 P25 FBI"
Conv, 1, 4, "145.17 DMR N2GKG"

Controls: Mouse wheel/click to select, Enter to tune, Esc to close. Right-click to tune and keep window open.

P25 Data File

Auto-generated P25 system information (v2.145+).

; Auto-records:
- System IDs and bandplans
- Site numbers and NACs
- Site BSIs and neighbors
- Channel usage (CC/SCC/voice/data)

Usage: If a monitored P25 control channel is not broadcasting bandplan data, DSD+ will retrieve it from DSDPlus.P25data. Can be manually edited to add bandplan data.

⚙️ Advanced Features

LRRP GPS Mapping

Location Request/Response Protocol visualization for radio tracking.

✓ Real-time position plotting
✓ Historical path tracking
✓ OpenStreetMap integration
✓ MaxAge control with [ ] keys

                    Run: LRRP.exe
                

Spectrum Survey

Analyze 2.4MHz chunks of spectrum over time.

✓ 3D frequency vs time display
✓ Peak/average level tracking
✓ Signal identification

                    In FMP24: Press Y then run Survey.exe
                

Per-Call Recording

Automatically record individual calls with metadata.

✓ WAV or MP3 output
✓ Aliases in filename (-PTwav, -PRwav, -PBwav)
✓ SRT subtitle generation
✓ Metadata headers in audio files

                    Command: -Pwav or -Pmp3

                    With aliases: -PTwav (talkgroup), -PRwav (radio), -PBwav (both)

Talker Alias Server

Cloud-based alias decoding for Motorola scrambled aliases (v2.505+).

✓ Unscrambles Motorola aliases
✓ Shares data between DSD+ users
✓ Harris alias decoding
✓ Offline buffering supported

                    Requires: Internet connection

                    Control: Misc Menu → Alias Server

Command Line Options (Current Version)

Active Parameters

                            -r1
                            Single receiver mode
                        
                            -rc
                            Control channel role
                        
                            -rv
                            Voice channel role
                        
                            -e
                            Mute encrypted voice
                        
                            -i<linkID>
                            Direct connection mode
                        
                            -iT<addr:port>
                            TCP link to remote PC
                        
                            -F<num>
                            File modifier (multi-instance)
                        
                            -P<T|R|B><wav|mp3>
                            Per-call recording w/ aliases
                        
                            -p
                            Manual polarity (use with -p-)
                        
                            -p-
                            Disable auto polarity detection
                        
                            -f<a>
                            Auto-generate audio output
                        
                            -<num>
                            Window minimization bitmap

Removed Parameters (Do Not Use)

                            -t, -T, -E
                            Removed v2.516
                        
                            -dr, -dh
                            Removed v2.29
                        
                            -mp
                            Removed v2.145 (now auto)

Menu Replacements

Many old command line options are now menu-controlled:

• Console/log controls → Misc menu
• Call priorities → Control menu
• Window/text sizes → Window menu
• Threshold, polarity → Active keys

Essential Keyboard Shortcuts

Key	Function	Context
`L`	Open Site Loader	Quick tuning to sites/channels
`C`	Toggle CC Hunt	Switch between CC-only and voice following
`E`	Mute Encrypted	Silence encrypted transmissions
`V`	Call Alerts	Toggle call alert sounds
`T` / `t`	Threshold +/-	Adjust decoding threshold
`↑` / `↓`	Audio Volume	Increase/decrease output volume
`P`	Invert Polarity	Flip signal polarity manually
`B`	Hide Traffic Mode	Toggle traffic display filtering
`G`	New Tg High Priority	Set new talkgroups to high priority
`U`	Check Updates	Verify current version online
`H`	High Contrast	Toggle high contrast display mode
`?`	Help	Show keyboard shortcut reference

🎛️ FMP24 / FMPA / FMPP Controls

FMP24 (RTL-SDR)

t Toggle bias tee

E CPU loading mode

L I/Q dropout test

p/P PPM correction

A Auto center tuning

Y Spectrum survey

Serial select: -i"serial"

FMPA (Airspy)