Standard Engineering Installation Package for Dual Frequency Signaling Unit (DFSU).
Abstract
The U.S. Army Communications-Electronics Installation Agency is responsible for engineering and installation of the Dual Frequency Signaling Unit (DFSU) communications-electronics (C-E) equipment at new and existing U.S. Army facilities worldwide. This Standard Engineering Installation Package (SEIP) will provide engineering and installation data, site survey criteria, quality assurance provisions, and test plan guidance in preparing an Engineering Installation Package (EIP) for installation of the DFSU. The purpose of the DFSU is to provide enhanced in-band supervisory signaling capability over voice frequency (VF) communication circuits. The existing (conventional) in-band signaling equipment utilizes a single frequency (SF) technique whereby a 2600 Hertz (Hz) tone is placed on the circuit to indicate the idle state (on-hook) and the tone is removed from the circuit to indicate the busy state (off-hook). Signaling states are conveyed via E (receive) and M (transmit) leads to the telephone equipment terminating the circuit. The DFSU operates in much the same way as SF units except that whenever the 2600 Hz tone is removed from the circuit a 2800 Hz tone is applied for a short period (175 milliseconds maximum).
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 15, 1982
- Accession Number
- ADA125418