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This appendix contains the following sections:
ISDN cause codes
ISDN cause codes are numerical diagnostic codes sent from an ISDN switch to a DTE. These codes provide an indication of why a call failed to be established or why a call terminated. The cause codes are part of the ISDN D-channel signaling communications supported by the Signaling System 7 supervisory network (WAN). When you dial an ISDN call from the MAX, the MAX reports the cause codes in the Message Log status menu. When the MAX clears the call, a cause code is reported even if inband signaling is in use. If the PRI or BRI switch type is 1TR6 (Germany), see Table A-2.
Table A-1 lists the numeric cause codes and provides a description of each.
Common problems and their solutions
This section lists problems you might encounter and describes ways to resolve them. It categorizes common problems as general problems, configuration problems, hardware configuration problems, ISDN interface problems, and problems indicated by the LEDs. General problems
DO menus do not allow most operations
When the list of DO commands appears, many operations might not be not available if the right profile has not been selected. Because the MAX can manage a number of calls simultaneously, you might need to select a specific Connection profile, Port profile, or Call profile in order to see certain DO commands. For example, to dial from a Call profile or a Connection profile, you must move to the Call profile (Host/6 > Port N Menu > Directory) or the Connection profile and press Ctrl-D 1. POST takes more than 30 seconds to complete
In earlier versions of the software, the MAX downloaded the required code and immediately commenced with AT POST (which sends the string AT to each modem and waits for the modem to respond with "OK"). With the current software, the MAX downloads the modem code, waits for the modems to checksum the downloaded code, and then verifies that the checksum matches before continuing. If the checksum does not match, the MAX downloads the code again, up to two more times. If the checksum still does not match after three download attempts, the MAX fails the entire slot card. Configuration problems
The most common problems result from improperly configured profiles. Some channels do not connect
You might encounter a problem in which the Line Status menu shows that the MAX is calling multiple channels simultaneously, but only some of the channels connect. In this case, an international MAX placed the call, or the call was from the U.S. to another country. In some countries, setting the Parallel Dial parameter in the System profile to a value higher than 1 or 2 violates certain dialing rules, and only some of the channels can connect during call setup. Try reducing the Parallel Dial parameter value to 2. If the problem persists, try reducing it to 1. Data is corrupted on some international calls
You might notice that the data appears to be corrupted on single- or multichannel calls dialed from the U.S. to another country. On some international calls, the data service per channel is not conveyed by the WAN to the MAX answering the call. You must therefore set Force 56=Yes in the Call profile. If you do not, the MAX incorrectly thinks that the call uses 64-Kbps channels. Only the base channel connects
You might encounter a problem in which the first channel of an inverse multiplexing or MP+ call connects, but the call then clears or does not connect on the remaining channels. No Channel Avail error message
If the error message No Channel Avail appears in the message log display when the MAX tries to place a call, check the Line N profile configuration. This message can also indicate that the lines' cables have been disconnected or were installed incorrectly. Restored configuration has incorrect RADIUS parameters
On earlier RADIUS Servers, the submenu consisted of three clients (specific host addresses) and one Server Key for all three clients. If the MAX supports the new RADIUS Server, the restoration of the MAX configuration will cause a problem, because the new RADIUS Server allows up to nine addresses (host or net) and a Server Key for each address. When you restore configurations with the old Client Address list, the subnet mask assigned to the clients will be the default subnet mask of the address type given (for example, 128.50.1.1 will get a subnet mask of 16) and not the previous 32-bit (single host) address. In addition, the Server Key will not automatically be set. You must set the Server Key manually for each client in the RADIUS Server submenu. Hardware configuration problems
If you cannot communicate with the MAX through the VT100 control terminal, you might have a problem with terminal configuration, the control port cable, or the MAX hardware. Cannot access the VT100 interface
If no data is displayed on the VT100 interface, verify that the unit completes all of the Power-On Self Tests. Proceed as follows:
If the Fault LED remains on longer than a minute, there is a MAX hardware failure. A blinking Fault LED also indicates a hardware failure. Should these situations arise, contact Ascend Customer Service.
The control terminal plugs into the HHT-VT100 cable or the 9-pin connector labeled Control on the back of the MAX. If you are connecting to an IBM PC-like 9-pin serial connector, a straight-through cable is appropriate. Otherwise, you might need a 9-to-25 pin conversion cable.
If you are not communicating at all with the MAX, see whether you can establish communication after you have turned off all transmit and receive flow control at your terminal or terminal emulator.
The first and most critical aspect of the interface is the physical cable connecting the MAX to the line or terminating equipment. Typically, WAN interface cabling problems appear immediately after installation. If you are unsure about the cabling required, contact Ascend Customer Service. The Hardware Installation Guide for your MAX describes the general PRI and BRI interface requirements and lists cabling pin-outs.
In some countries outside the U.S., it is common for no logical link to exist before the MAX places a call. In the U.S., when you first plug a line into the MAX or switch power on, the central office switch can take as long as 15 minutes to recognize that the line is now available. You might have to wait that long for the line state to change to Active (A). The physical link can exist without a logical link up on the line.
If you wait longer than 15 minutes and the line is still not available:
If you are running multipoint (passive bus) on your switch, all of the ISDN telephone cables must be wired straight through. If any of the cables are wired to cross over, you will not be able to place calls.
Try both the 64K and 56K options for Data Svc, to see whether using a different value solves the problem.
Depending on how the BRI lines are configured, you might need to type four, seven, or ten digits to communicate with the remote end.
You can check link quality in the WAN Stat status window, or by running a Ping between the same endpoints. Dropped packets hurt the link's efficiency, as does round-trip delay. Random round-trip delay indicates heavy traffic, a condition that also drops the efficiency of the link.
Copyright © 1998, Ascend Communications, Inc. All rights reserved.