GAI-Tronics MRTI 2000 (No. PL1877A) Microprocessor Radio Telephone Interconnect Installation & Service Manual - Manual (Page 81)

PL1877A Microprocessor Radio Telephone Interconnect Operator Instructions
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Selective Signaling with Direct Channel Access
In this situation, the PL1877A grants direct channel access to the telephone user immediately after paging
the mobile. The telephone user has access to the channel for a certain time (the direct access duration).
At the end of that time, the PL1877A disconnects the telephone user.
The direct access duration can be extended to the normal, overall access duration (set by parameter 357)
in one of two ways. First, you can program the PL1877A (via parameter 25) to extend the direct access
duration if mobile carrier is detected. The other method of extending the direct access duration is to
require reception of a wildcard access code that includes the paged mobile’s capcode or user ID digits.
For example, suppose the PL1877A is operating in single-mode selective signaling and has just paged a
mobile whose QuickCall II capcode is 023. The telephone user has been granted direct channel access.
If the PL1877A receives a wildcard access code that includes some or all of the digits 0, 2, and 3, the
time allotted for direct access is extended to the overall access duration (parameter 357).
Suppose the PL1877A is operating in multi-mode selective signaling and has just paged a mobile whose
user ID is 56. The telephone user has been granted direct channel access. If the PL1877A receives a
wildcard access code that includes the digits 5 and 6, the time allotted for direct access is extended to the
overall access duration.
Programming the Wildcard Template for Use with Selective Signaling
To program the wildcard template such that the wildcard access feature functions as described for
selective signaling, follow the steps of this section:
1. If you wish to allow only the paged mobile user to answer a page (without direct access), restrict
mobile access to users of multi-digit access prefixes by setting parameter 38 to 1. Also, disable all
standard multi-digit access prefixes by setting parameters 362–385 to FF (hexadecimal FF).
2. Determine how many digits you want in wildcard access prefixes. The allowable range is 1–6.
3. Determine the manner in which the mobile’s capcode digits or user ID is to be encoded into the
wildcard prefix.
For example, suppose you have decided that wildcard prefixes are to consist of 5 digits represented
by X X X X X. Since the PL1877A is programmed for multi-mode selective signaling, you want the
2-digit user ID (represented by YY) to be encoded into the wildcard prefix. There are a number of
ways you can encode the user ID into the wildcard prefix. Listed below are just a few:
X X X Y Y Y Y X X X X Y X Y X X Y X X Y Y X X Y X
4. Fill in any remaining digits with specific digits or wildcard digits.
Suppose you have chosen Y X X Y X as your wildcard pattern. You must now determine what will
be placed in those locations marked by X. You may either place fixed digits (0-9, A-D) in these
positions or you may place wildcard digits (F) in them. Of course, you may also place a mixture of
fixed and wildcard digits in them. There are numerous possibilities for the resulting wildcard
pattern. Listed below are just a few.
Y 1 2 Y 3 Y 1 F Y F Y F F Y F