ACP-500 | Out-of-Band Network Switch

ACP-500 | Out-of-Band Network Switch


ACP-500 Out-of-Band Network Switch & Call Router –  5 telephony devices share 1 phone line

The ACP-500 is an industrial grade Out-of-Band Network Switch, Dial-up Gateway, and telephone line sharing device….three solutions in one for remote network support.

  • Eliminates costly dedicated phone lines for fast R.O.I.
  • Caller ID “Store & Forward”
  • Secures dial-up modems from unauthorized access
  • Automatically directs calls to phone, fax, modems
  • Streamlines polling and data acquisition
  • Provides barge-in capability for priority outbound calls

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Product Description

Reduce phone line costs, improve connectivity, and secure your telecom and network equipment with Multi-Link’s ACP-500 Out-of-Band Network Switch & Call Router (part of the new ACP Series 2.0).

Protecting access to information systems is becoming more critical in commercial and industrial applications, as are reliable, secure, and redundant communication paths. The ACP-500 provides these capabilities, while providing cost savings through phone line sharing (Line consolidation).

ACP-500 Basic Application v.11

Fig.1 ACP Basic Installation (ACP-500 shown)

Call Routing with the ACP-500

The ACP-500 automatically routes calls to phones, faxes, and dial-up modems, ensuring that the right resource is reached the first time. This consistent connectivity prevents time consuming dial-backs and streamlines polling and data acquisition processes such as SCADA, POS access, Substation/Revenue meter reading, Tank level monitoring, M2M communication, Submetering, and HVAC/Lighting control, etc. Multiple devices can share a single telephone line, eliminating costly phone lines and saving up to $50/month for each line eliminated. Businesses with multiple remote sites can realize a significant ROI in 3 months or less.

ACP-500 C-store Before & After

Fig.2 C-Store Before & After Line-Sharing

The ACP-500 Provides Secure Out-of-Band Access

The majority of Multi-Link’s phone/data line-sharing switches are being installed for out-of-band dial-up modem access to communication and data networks. When the network is down and normal in-band access is denied, how do you recover the network equipment? Remote out-of-band  access to management ports provides an efficient back door method for recovery. This can be through the use of a backup dial-up modem via the Public Switched Telephone Network (PSTN). Installed on an existing POTS line, the ACP-500 provides an inexpensive, secure and controlled “out of band” path for accessing service ports to network equipment. Why pay a monthly cost for a line that you never want to use?

ACP-500 Out-of-Band Application

Fig. 3 ACP Out-of-Band Application

The ACP-500 as a Dial-up Gateway

Protecting access to IT systems and networks is becoming more critical in commercial and industrial applications.The ACP-500 is engineered to provide an additional layer of security to connected devices.Vulnerable pathways to equipment via the PSTN are protected by programmable Security Access Codes up to seven characters. There are over 35 million combinations to choose from, effectively creating a telephony firewall for dial-up connections. Service vendors that need to monitor their on-site equipment can now have remote access that is completely isolated from the IT network. This is most advantageous for service vendors working with government agencies and businesses with strict IT security policies.

How does the ACP-500 work?

The ACP-500 is an industrial grade call processor with an advanced feature set designed to route calls on an analog/simulated analog telephone line. Upon ring detection, the ACP-500 will capture CID Data and answer the incoming call. After answering, the ACP-500 immediately scans for a CNG (fax) tone or DTMF security access code (SAC). During this processing period, a Bell spec “ring-back” tone is provided to the calling party. If a security access code (SAC) is detected, the call is routed to the corresponding device port. If a CNG (fax) tone is detected, the call is routed to the designated fax port (Device 2 port). In the absence of a CNG tone or security access code, the call is defaulted to the device 1 port. The original CID Data will be retransmitted after the first ring to any device port. All device ports have access to telephone line and outbound requests are performed in a standard fashion. Any device that tries to access the telephone line when the telephone line is in use will hear a busy signal. The emergency barge-in (EBI) feature allows the specified device port/ports to seize the telephone line and take priority in the event of a critical outbound call. This feature can be programmed ON/OFF (OFF by default) for devices 1 through 4 for the ACP-500 & ACP-900 units (1 through 3 for the ACP-300).

Regarding the Emergency Barge-In Feature of the ACP Series 2.0: Please note that the Emergency Barge-In operation of the ACP Series 2.0 may not be optimal for achieving line seizure when used on the PRIMARY connection in applications involving emergency security equipment, e.g. fire, medical, police, first responder, or critical monitoring notification. Always validate approved connections with the appropriate local jurisdiction/ordinances and the Insurer of the business/property. If you choose to utilize the ACP Series 2.0 on a primary connection, it is highly recommended that all equipment involved is thoroughly tested and in compliance prior to final activation. Questions? Call us at 800-535-4651 for further information.

Key Benefits

Key Features


Key Benefits

• Reduces or eliminates costly dedicated phone lines for fast R.O.I.
• Hacker Shield Protection secures dial-up modems from unauthorized access
• Control remote management port access for service vendors
• Automatically directs calls to phone, fax, or modems
• Streamlines polling and data acquisition processes

Key Features

HACKER SHIELD PROTECTION– Programmable Security Access Codes, up to 7 digits per port, protects connected devices from unauthorized access for a robust telephony firewall.
Caller ID “Store & Forward”– CID is sent to device on first ring.
Multiple Line Seizure Ports– Up to four device ports can now be designated for emergency line seizure for critical applications.
LED Status Display– Seven segment display shows port in use & programming value read-back. Audible read-back tones are also provided for remote programming.
Data Disruption Protection– Prevents active calls from interruption by another device.
Remote Programming– ACP’s can be securely programmed by a remote administrator.

Standard Features

Bell Spec Ring-Back Tones
Dual Surge Protection
No Software to Install
Mounting Bracket Included
2 Year Warranty


• Out-of-Band Network Access
• Telephony Firewall
• Dial-Up Gateway
• Utility Meter Reading
• Remote Site Management
• HVAC Control Monitoring
• Substation Communications
• Point-of-Sale System Integration
• Modem Polling
• Fuel Tank Monitoring
• Service Port Access
• SCADA Interrogation
• 1st Line Network Support

Download The ACP Series 2.0 Data Sheet (PDF)

Download ACP Series 2.0 User Manual (PDF)

Phone Line Cost Savings Calculator (Link)

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