ConneXions CX5 DC, Multi Port Version
CX5DCred
Issue 2
Page
12 of 13
Section 3: Technical Information
This section provides a more in depth understanding of how messages are formatted for serial
communication from a host. It need only be studied by those intending to write their own serial
comm.’s software.
Calling Pagers
Pagers all use 7 digit numeric addresses which enables the system to support thousands of pagers
without identity clashes. Most pagers will support multiple addresses (sometimes referred to as CAP
codes, RIC’s or identities). This enables the pager not only to respond to its own unique address but
also to respond to group or global addresses.
These
real
7 digit numeric codes are often substituted for shorter
logical
numbers which are easier
to remember. Under these conditions the host or speciality program within the transcoder will perform
an algorithm on the data string received to convert the simpler
logical
number back into a
real
7 digit
number for transmission.
For improved data recovery without error the
real
7 digit pager numbers are always spaced 8 digits
apart.
To avoid system identity clashes, transcoders are provided with a base number within the range of
1000 to 1,999,000. If for example a base address of 0100,000 is applied to a transcoder, the first
real
pager number will 0100,008 followed by 0100,016 and so on.
Logical pager numbers are normally used on systems fitted with the telephone interface and those
which are interfaced to personal computers. The algorithm would perform the following function:-
For example take the
logical
pager number of 123
The
logical
pager number 123 will be multiplied by 8 and then added to the base number to provide
the 7 digit
real
number
Logical
No
Base No
Real
No
123 x
8
=
984 +
0100,000
=
0100984
Pager address 1 is normally reserved as the personal identity for that specific pager. Other
addresses, of which there can be 6 or more, can be tagged to specific pagers to form selected
groups. Address 2 could, for example, be used for all pagers to formulate a global call.
Address codes can be divided between full addresses and sub addresses. Full addresses can allow
four different bleep types, A, B, C or D, whereas sub-addresses will only accommodate a fixed bleep
type. A status line of information will normally be provided on the pager screen which will highlight
the type of bleep sent together with other status information.
Numeric Pagers
Example serial message string:-
N0012300A1234567890<CR>
The ‘N’ informs the transcoder that this message is destined for a Numeric pager. Any data not
preceded by this will be ignored.
