[bmxmike]

Description of the ACCOLC.

Saw this and got kinda confusing so did some research of my own...Not sure how true this is but what i gathered.

It's primarily for controlling the reverse control channel link.
Each of the 16 values (0 to15) on the phones corresponds
to a flag bit In the "overload control global action message "
There is a total of 16 flag bits in the Global action message.

It is not hierarchical!

When a flag bit is set high, the phones with that ACCOLC setting
will be in serve mode.
They will place calls when the user request.

When the bit is low, the phone will not accept a call request from the user.
When a user request a call, the phone will respond with the fast busy
signal.

Any of the flag bits can be high or low, with no correlation to other bits.

If the 16 bit control word is, 1010-0000-0011-1111.
Only phones with the ACCOLC of 1, 3, 11, 12, 13, 14, 15, and 16
will accept request for placing a call.

It doesn't have to restrict the phones based on a hierarchical system.
(ie) It can allow level 1 access while disallowing level 5 access.

Incoming calls are regulated by the cellular network.
The phone still monitors the control channel for incoming calls and
new global action messages, but it will refuse to accept a call request
from the user.

The practice of using the last digit of the phone number will evenly
distribute the current users into 10 groups.
When incoming request grow beyond capacity, the control channel
can basically disable users in 10% increments.
It is up to the control station to rotate the blackout among the
10% chunks that reside on each overload class.
Or the control station can lock out a group, or all groups
for as long as it wants.

Presumably with bit 10 in the high condition all the time to
allow emergency personnel unrestricted access.

When you dial 911 on an AMPS, CDMA, TDMA, GSM phone, it will
ignore the global action message and proceed to initiate a call
as soon as the control channel finishes serving the current phone
that it is talking with.
That is why you have a setting on AMPS
(and newer) phones
for the emergency number.
When you dial that number, it will ignore any ACCOLC or global action
messages, and it proceed to initiate the call .

The ACCOLC is supported on AMPS, TDMA, CDMA, and GSM.
It is used for a different purpose in the UK for GSM phones
but it still has the same 16 bit control system.
And no modifications have to be made to the phone
for it to work on the US system or the UK system.

When you get a recording that all lines are busy on the cell phone,
Then ACCOLC is not being utilized.
The wireline connection to the tower is what is beyond capacity.
When you get the fast beep, then the ACCOLC is being utilized,
And your phone is currently being restricted by the tower,
because their is no more frequency slots available..

Hope everyone will learn as much as I have off of this.

This also mean's the higher your number the more importance you may have