SIP Analog Modem Server – Alarm Panels

SAMS with Voice Command Set enables alarm panel monitoring over VoIP connections

The comprehensive modem feature set of VOCAL’s SIP Analog Modem Server (SAMS) enables interoperability with standard alarm panel protocols utilizing SIP based VoIP connections. Alarm panel monitoring functionality is realized by combining VOCAL’s alarm panel optimized modulations with V.253 Voice Command Set interface.

VOCAL’s Voice/Alarm Command Set extension creates a simple interface to pump level functions which are not exposed by standard AT command set interfaces. This allows the alarm panel communications software to perform the operations required by various protocols. The interfaces unlocked with the Voice/Alarm Command Set include the ability to transmit and receive audio directly over the VoIP connection, detection and generation of DTMF signals with control over on-off cadence of each tone, precise tone generation and detection, disconnect tone detection, and the ability to transition from voice mode into data modulations.

Combining SAMS with the Voice/Alarm Command Set unlocks the ability to transition legacy alarm panel monitoring stations away from expensive POTS connections which utilize physical hardware and into modern cloud-based VoIP infrastructure. Alarm panel optimizations facilitate timing resiliency by spoofing intended application responses where timing is critical.

Ademco Contact ID

The Ademco Contact ID (CID) protocol, also known as SIA DC-05, relies on precise handshake tones followed by DTMF message transmission and kissoff tone message acknowledgement. CID requires both the DTMF and precise tone generation and detection capabilities of the Voice Command Set. This common protocol is utilized across many Ademco variants including Standard 3×1 and 4×1, Extended 3×1 and 4×1, 3×2 and 4×2, etc.

SIA Format

The SIA Format protocol, also known as SIA FSK, SIA DC-03, or Digital Communications Standard (DCS), is implemented using a combination of ITU-T V.21 modulation with handshaking and kissoff tones. SIA Format can support both 110 and 300 baud variants of V.21 and it utilizes a special synchronization signal to select the proper rate on a per call basis. For SIA Format capabilities a modem must support generation and detection of the speed synchronization signal as well as the handshake and kissoff tones. SIA Format support is available in SAMS alarm panel packages.


The Sonitrol protocol utilizes Bell 103 style data transmission and reception along with audio pass through. The Sonitrol protocol requires the SAMS data modulations customized for alarm panel monitoring as well as the voice-data mode transition capability of the Voice Command Set.

SIA 2000

The SIA 2000 alarm panel protocol, also known as SIA DC-04, utilizes standard Bell and ITU modulations for data transfer. VOCALs alarm panel optimized automode startup procedures ensure proper rate and modulation selection.

Alarm Receiver

VOCAL’s SAMS software can be utilized as Voice over IP based alarm panel receiver appliance. Alarm panels, connected via traditional analog POTS lines, can dial across the public telephone network and reach a VoIP connected SAMS server to deliver their alarm reports. VOCAL’s SAMS receives the alarm reports and delivers them via virtual COM ports or virtual TTY devices to traditional alarm receiver software. Additionally, SAMS can be used to dial out into the field alarm panels for remote configuration and maintenance. VOCAL’s SAMS is a fully software-based alarm receiver solution that creates a migration path to cloud environments by removing expensive server-side receiver equipment, as well as the need for dedicated E1/T1/POTS lines.


The fully software based architecture utilized by SAMS combined with decades of experience with data modems and telecommunications means that VOCAL can customize interfaces and functionality as required by any Alarm Panel Protocols.

• 100% software solution easily migrates to the cloud
• Voice Command Set for Alarm Panel Monitoring control
• Precise tone detection and generation
• Runs on any standard Linux and Windows distribution
• DTMF detection and generation
• Replaces RAS equipment configurations when analog lines are being replaced with VoIP (SIP/RTP) lines
• Scalable – enables a large number of modems on a single server (10s to 100s depending on the server and modem rates)
• Exports TTY (com port) interface for each modem
• Each TTY accepts industry standard AT commands – V.250, Industry Standard
• Registers with one or more SIP servers (can be phone number per line, modem pool hunt, or other combinations)
• SRTP and Secure SIP options available
• Dialing commands will make outgoing SIP/G.711 call (with modulation data in the stream)
• Incoming SIP calls will report RING to applications listening to TTYs
• Requires no analog audio interface
• Slaves to far end modem clock to eliminate skew
• High speed data modulation – V.34, V.90, V.92 (optional)
• Low speed data modulation – V.32, V.32bis, V.22, V.22bis, V.23, V.21
• Bell modulation – Bell 212, Bell 103
• Supports standard protocols such as V.42 / LAPM, MNP 2-4
• Supports standard compression protocols such as V.42bis and MNP5
• Supports industry standard protocols, such as DC-03 (SIA), DC-04 (SIA 2000), DC-05 (Contact ID), PULSE, FSK
• Customized modulations for Alarm Panels

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