User's Manual

545C Operations Manual

02/10/2012 Prerelease DCN 00001789-A

$DIR, p, m, s, n

Packet 1 1 1 0

Packet 2 1 2 0

Packet 3 1 3 3

Messages may be transmitted from one to four destinations. When a

DIRECT message is received at the destination MCC-545C, it will be routed

to the assigned port(s) (Operator, Data or AUX). There are two types of

connections that may be used: point-to-point and multi-point-to-single-

point.

Point-to-Point

In the point-to-point mode the destination MCC-545C must also be pre-

programmed in the DIRECT mode. When the message is received at the

destinations, the $DIR,p,m,s,n header will be removed from the message

and the message will be routed to the same port that was used at the

source. That is, messages that were originated on Port 1 must also be

routed to Port 1 at the destination.

The destination unit can respond with its own character stream back to the

source. This provides a direct point-to-point, bi-directional channel

between the two stations. The embedded ETE acknowledgement in the

ELOS protocol may be used for ensuring message delivery.

Multi-Point-to-Single-Point

Many remotes can be set up to operate in the DIRECT mode, all routing

their data to a common destination (base station or Host). The destination

station does not have to be pre-programmed in the DIRECT mode as in the

point-to-point case. The destination station will treat the message as it

would for any other text message, using one of the many available port

protocols. The message header, $DIR,p,m,s,n, is retained with the message

so that the destination station will know how to format a return message to

the source station. In this manner, the Host can send response packets to

all sources by appropriately formatting the message header.