Filter
Top Products
Appendix E: M3110, M3310, and M3820 telephones Page 487 of 504
Telephones and Consoles Description, Installation, and Operation
Line engineering
Meridian digital telephones use twisted pair wiring on transmission lines
selected by the rules given in “Digital telephones line engineering” on
page 289. The maximum permissible loop length is 3500 ft. (1067 m),
assuming 24 AWG (0.5 mm) standard twisted wire with no bridge taps. A
15.5 dB loss at 256 kHz defines the loop length limit. (Longer lengths are
possible, depending on the wire’s gauge and insulation.) Table 81 gives
detailed information on loop lengths.
Note: Use only the line cord provided with the telephone. Using a cord
designed for another telephone could result in damage to the cord.
Local alerting tones
Each telephone provides four alerting tones and a buzz sound. The system
controls the ringing cadence by sending tone-ON and tone-OFF messages to
the telephone. The alerting tone cadences cannot be changed from the
telephone but can be altered for individual terminals by software controlled
adjustments in the system. See Software Input/Output: Administration
(553-3001-311). All other telephone tones, such as dial tone or overflow, are
provided by the CS 1000 and Meridian 1 systems from a Tone and Digit
Switch.
Table 81
Loop lengths for Meridian digital telephones
QPC578 A and B QPC578 C + NT8D02
PVC insulated cable (polyvinyl chloride)
22 or 24 AWG 100–3000 ft.
(30.5–915 m)
0–3500 ft.
(0–1067 m)
0–3500 ft.
(0–1067 m)
26 AWG 100–2100 ft.
(30.5–640 m)
0–2600 ft.
(0–945 m)
0–2600 ft.
(0–793 m)
Note 1: No bridge taps or loading coils are allowed.
Note 2: Effect of line protector at MDF reduces loop length by 500 ft.