Q: How do I order ISDN service?
A: For information on ordering ISDN service for the 3ComImpact External digital modem, request document number 2620 from 3ComFacts at (408) 727-7021.
Q: How many devices can be attached to the 3ComImpact digital modem's analog phone port?
A: The analog voice port on the digital modem supports a Ringer Equivalence Number (REN) of 3. This means that 3 standard line telephones with mechanical ringers can be operated from the digital modem to a maximum distance of 100 feet. Newer telephone products provide electronically simulated ringing and thus require much less ringing voltage from the analog port. While multiple devices such as analog telephones, answering machines, and fax machines can be attached to the voice port using an RJ-11 splitter, only one device may be used at a time.
Q: Is compression supported?
A: Compression is not currently supported.
Q: Does the 3ComImpact External digital modem support Data Over Speech Bearer Service?
A: Yes, Release 2.02 of the digital modem supports data over voice (switched 56 permissive). This feature applies to outgoing calls only and the equipment that the digital modem dials into must support this as well as be capable of generating the 2.1 kHz tone required for this feature to function properly.
You can set up the digital modem so that all outgoing calls are data over voice calls or you can place a data over voice call on a call by call basis. If you want all outgoing calls to data over voice, set S register 61=1.
To place a data over voice call on a call by call basis, send the AT command ATDD (telephone number) to the digital modem.
Q: Can the 3ComImpact External Digital Modem coexist with my analog modem inside my computer? (Applies to models 3C871 and 3C876 only)
A: Yes and if you only have one telephone outlet, remember to plug your internal modem's telephone cable into the digital modem's analog port. (If you have another telephone line outlet you could plug your modem's phone cable into it.) Also, ensure that different COM ports are used.
Q: Why is it that I cannot place or receive voice calls?
A: The digital modem is designed to operate with telephones that are compatible with the original AT&T 2500 touch-tone telephone standard. If you are attempting to use a portable telephone that does not conform to the AT&T 2500 touch-tone telephone standard, you may not be able to place and/or receive voice calls. Also, check with your local telephone company to ensure that your ISDN line has been provisioned for circuit switched voice on both B channels.
Q: Why is it that I can receive voice and data calls but cannot place them?
A: Please find out from your telecommunications coordinator if you are on a private network (e.g., Centrex). If this is the case, you may need to prefix all dialed numbers with a digit such as 9. This will give you the capability to place calls to destinations outside of your private network.
Q: Why is it that I cannot place any long distance calls?
A: Check with your ISDN line provider to ensure a long distance carrier (e.g., AT&T, MCI, Sprint, etc.) was selected for your new ISDN line.
Q: Why is it that I cannot use my fax machine?
A: Make sure you are using a Group 3 fax machine. Check the documentation which came with your fax machine.
Q: Why is it that I can dial my phone operator (by pressing zero) but I cannot dial anyone else, nor receive any voice calls.
A: Ask your telecommunications coordinator if you are on a private network (e.g., Centrex). If so, you typically need to dial a number such as 9 before you can place a call.
Another cause may be a problem with the telephone. Ensure that your telephone conforms to the AT&T 2500 touch-tone telephone standard. If it does, verify that it is working properly by connecting it to another telephone jack or by substituting the telephone with another telephone.
Q: Can I plug my ISDN telephone into the 3ComImpact digital modem's analog phone port?
A: No, the Phone Out port only works with analog devices.
Q: Is it possible to have a 56 Kbps/64 Kbps connection and a modem (3ComImpact digital modem's internal analog modem) connection simultaneously?
A: No, you cannot make an ISDN and an analog call through the data port on the digital modem simultaneously.
