Pacific Research Solutions RI-200 - Manual (Page 63)

Pacific Research Solutions RI-200 User Manual
Page 62
TELEPHONE INTERCONNECT
6.0 TELEPHONE INTERCONNECT
The RI-200 incorporates a highly intelligent telephone interconnect. This interconnect used a full duplex hybrid that is
balanced each time an outgoing call is started. A telephone hybrid is a circuit that separates the transmit and receive audio
from the telephone line before it is sent to the radio. Most hybrids are adjusted for maximum performance at the time of
manufacturing. Over time and various telephone lines the performance of the hybrid is compromised. In the RI-200 the
hybrid is balanced by the micro controller each time an outgoing call is initiated.
The RI-200 has an AGC (Automatic Gain Control) that is used to automatically adjust the audio level from the telephone
line. The micro controller directly controls this AGC. The software monitors and avoids conditions that would cause
pumping of the audio, a common problem with most other AGC circuits. You can set the initial level of the AGC and the
controller will operate in a smaller range of this course setting. If the telephone audio is typically too low or too high, you can
adjust the overall range of the AGC. You can also turn off the AGC, see S-Command 79.
During the dialing process the controller will check for dial tone. If dial tone is not detected within the set time, the
controller will start dialing anyway. You can also set the controller in an auto dial tone detect mode. In this mode the
controller will give a busy message if the dial tone is not detected. This mode could be used if the telephone line is shared
with someone else and you want to check the telephone line for use before dialing.
When you start the call process, the controller performs several tasks before the telephone audio is connected to the repeater.
1. The user enters the telephone user command and telephone number to be dialed.
2. The controller checks the number to dial against the accept and reject tables.
3. The controller checks for dial tone.
4. The controller checks the access table for an access number to dial.
5. The controller checks to see if an auto dial number needs to be dialed.
6. The controller checks to see if a user entered number needs to be dialed.
7. The controller checks the account table for an account number to dial.
8. The controller balances the hybrid to the telephone line.
9. The controller sets up all of the time-out timers for the telephone call.
10. The controller connects the telephone audio to the repeater.
6.1 TELEPHONE INCOMING CALLS
The RI-200 supports both incoming and outgoing call modes. Under the incoming call mode, you can setup how the
controller deals with an incoming call. The controller can be disabled from receiving a call or requiring a password, CTCSS
tone and DTMF sequence to ring the repeater with various modes in between. Under the most sophisticated mode, you can
selectively ring an individual radio. Up to 154,000 unique rings (154 different CTCSS tones / DCS codes and 3 digits DTMF
string). Most of the incoming call modes can be setup to require a password from the caller, limiting a caller’s access to the
repeater. In some incoming call modes, you can use a control password and then send commands in the same manner that
you would control the repeater over the radio. This mode would allow you to configure, write macros, issue user commands
and S-Commands over the telephone. Review section 4.5.71 for more details.
In any of the incoming call modes, the ring delay counter (S-Command 75) must expire before the controller will begin
ringing on the repeater. In S-Command 71 modes 2 through 4 the controller will answer the call before any actions are
taken, repeater ringing or password requirement. Once the repeater starts ringing form an incoming call, the total number of
rings can be limited by S-Command 76. In mode 5 the controller will answer the call and connect it directly to the repeater.
This mode is called auto answer. For this mode to operate correctly, the controller must be told where the answer telephone
macro is located. This is done with S-Command 32 event 19, the current default will correctly answer the telephone.