Power-Fail Transfer

Powerfail TransferModels 154 & 154A Powerfail Bypass

Peace of mind protection during equipment failures

Installation Instruction (pdf)
Product Brochure (pdf)

The “154” products transfer up to 8 system phones to CO trunks when the power or phone system fails. All connections are isolated from the phone system while in Bypass mode. You may install multiple units to handle more than 8 trunks. The 154 requires a 48V power supply. The 154A requires a 24V power supply (optionally included).

Both models also act as Automatic Loop-Start to Ground-Start Converters, allowing loop-start equipment to work on ground-start trunks without requiring a button. This mode is available with or without the transfer function.

The 154 works with ground-start or loop-start trunks. Ground-start detection is automatic. No configuration is required. Transfer can be activated by power failure, a manual bypass switch, or a switched ground from the phone system or a remote location. The 154 can also control auxiliary equipment (and/ or other 154’s) with two sets of dry relay contacts available.

When the power is returned, the Model 154 will restore only those powerfail trunks that are idle. In-use trunks are restored only after they become idle. Calls are never lost a second time!

Don’t be fooled by Uninterrupted Power Supplies (UPS). They only protect against power outages. The 154 provides full protection against system equipment failures as well as power outages.

The 154 and 154A are identical apart from the power supply voltage. See Ordering Information chart for complete model numbers.

Every successful organization thrives on efficient communication links with clients and suppliers. If you fall into this category, you cannot miss a call. It could be a customer calling with an order or a supplier calling with a delivery date. Communications by telephone lines, whether voice or data, are crucial to a business’s success. That’s why power failure can hurt your company.

When the power goes out, your communications link with the rest of the world is severed unless you have the Model 154 Powerfail Bypass unit installed in your facility. It’s the obvious solution for every business and organization. When the power goes out, or you have a major alarm, you will continue to receive calls and business goes on as usual. You can even control auxiliary equipment using the Model 154 such as an auto-dialer to inform another branch or customer that your power is down.

If your application doesn’t use the Transfer function, no power supply is required.

154 Installation


  • Connects dedicated telephones directly to Central Office during powerfail or major alarm
  • Automatic ground start
  • Calls in progress are not interrupted when power is restored
  • Parallel connections simplify installation
  • Activated by powerfail, manual bypass switch or remote ground
  • LED power indicator
  • Can be remotely activated
  • 2 sets of auxiliary contacts, one normally open, one normally closed


Ordering Information

Model 154-8 8-Trunk Powerfail 48VDC
Model 154A-8/PSU 8-Trunk Powerfail 24VDC with Power Supply (Model 368)


Min Typical Max Unit
Operating Supply Voltage
Model 154-8 40 56 VDC
Model 154A-8 20 28 VDC
Operating Supply Current
Model 154-8 100 mA (DC)
Model 154A-8 180 mA (DC)
Loop Current 20 120 mA (DC)
Auxiliary Contacts
Current 2 A (DC)
Voltage 30 VDC
Power 30 VA
Operating Temperature 32 158 °F
(intended for indoor use only) 0 70 °C
Humidity (non-condensing) 95 % RH

Unit Dimensions (LxWxH)
9.25” x 5.40″ x 1.58″ (23.5 x 13.7 x 4 cm)

Shipping Specs Weight


154-8 1.8 lbs.
(0.82 kg)
10.75″ x 6.375″ x 3.375″
(27.3 x 16.2 x 8.6 cm)
154A-8/PSU 2.2 lbs.
(1.0 kg)
10.75″ x 6.375″ x 4.375″
(27.3 x 16.2 x 11.1 cm)



Approval Number

DOC CS03 350 1976 A
CSA C22-2 No. 225-M90 LR 65726
FCC Part 68 FCNCAN-22540-OT-N
UL 1459-2 D05921080C and D0292442DBC

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