Microwave Radio - Nortel Meridian 1 Manual

Microwave radio

Cabling between the SL-1 and the carrier facility should meet the criteria
outlined for land-line carrier systems. In addition, the complete microwave
system must also meet the overall limits for land-based carrier systems, and
should conform to T1 interfacing specifications.
As in land-line carrier systems, the distance at which the SL-1 can operate is
governed by a 1.5-ms timeout in the peripheral signaling card when
interrogating the peripheral equipment. This 1.5-ms value is the maximum
total round-trip time allowable, including propagation time and any delay
introduced by signal processing at microwave stations. The maximum
allowable distance (in miles) is given by:
M x V – D
where
M = maximum allowable delay (ms)
V = propagation velocity (mi/ms)
D = any other processing delays (ms)
Example
In the case of a land-line system, assume that the maximum allowable delay
(M) is 1.25 ms to give a safety margin of 0.25 ms. The propagation velocity
(V) of signals through wire is 115 mi/ms. Assume that there are no delays (D)
in the system. Thus the maximum allowable distance is 143.75 mi, as
follows:
(1.25 ms x 115 mi/ms) – 0 ms = 143.75 mi
Carrier interface
RPE Description, installation, and testing
Page 41 of 60