Below follow some reviews of ISDN communication products. The opinions expressed are solely those of MSGNet, and are the result of hands-on testing of the equipment through an Ameritech 5ESS switch (in DMS-100/NI1 emulation).
Criteria include ease of use, compatibilty, POTS support, and reliability. Your mileage may vary. For information on terms, see the glossary
Combinet 2060 (Now CiscoPro) Gandalf LanLine 5242i
Cisco 1004 Livingston PM-2
Adtran ISU Express ZyXel Elite 2864I Motorola BitSURFR Pro USR Sportster 128The Combinet 2060 is an ISDN LAN bridge that includes basic PPP support as well as proprietary protocols. The 2061 variant provides one POTS jack.
Configuration is by command-line interface, serial port or remotely from another Combinet product. the user interface has notably improved between the 2.4 and 3.0 software release.
Shortly before their acquisition by Cisco, Combinet began to provide router-like features on the 206x, including software licensing based on number of IP addresses.
Well rounded product, good security, relatively easy to configure
The Gandalf 5242 Bridge is an ISDN LAN Bridge with PPP support as well as proprietary protocols. The bridge includes one POTS jack.
Configuration can be done with a DTMF phone on the POTS jack, SNMP or through a full-screen interface accessibly by the serial port or telnet. The keys used to control this interface are confusing at best, using function keys and odd control sequences.
Gandalf's proprietary compression protocol provides impressive throughput, and SecurID is implemented on the server-side, so any remote bridge can be used with Gandalf servers (not reviewed here).
You might wish to see Gandalf's blurb.
Reliable router. Fine if you're an expert in Cisco's IOS or know an expert
to configure it for you.
The Cisco 1004 is a miniaturized Cisco Router, and provides the same PPP and HDLC options as do the full versions.
Configuration is by SNMP and the classic Cisco command-line interface. Setup can be difficult even for experienced Cisco users, there is a comprehensive Dial-On Demand Routing document on their web site.
Cisco has a Press release
While Livingston is best known for their line of serial terminal servers,
including the PM2e and new PRI model, the PM3, they also produce routers.
The PM-2E 5-BRI ISDN card replaces one of the three 10-port serial cards, allowing the use of up to 5 BRI lines for accepting calls from other ISDN equipment (BRI does not accept analog modem calls).
ISDN Terminal adapters generally have a DB-25 serial port supporting both synchronous and asynchronous connections, there are a few available as internal cards or with parallel port connections.
TA's that have POTS support almost universally are very slow to detect hangup- the phone needs to be on hook for several seconds to 'register' as a hangup, probably due to the need to distinguish between the 'flash' (click the switchhook once) and a true hangup.
Many allow they user to specify a list of (usually 10) Caller-ID numbers to accept/deny calls from, and generally will also send the calling number on the serial port after the RING message. Few terminal adapters will translate the ISDN Caller-ID signal to analog for use with regular Caller-ID boxes.
Reliable TA, good for consumer use.
The Adtran ISU express is an ISDN TA with optional POTS jack and/or 14.4 Modem, it provides V.120 and sync-async PPP conversion.
Configuration is by AT commands and/or full-screen serial interface. The full screen interface is easy to use, and includes a status screen logging the most recent messages (including incoming and outgoing calls with phone number and results).
Extra phone features including 3-way calling, call waiting, and call transfer can all be used via the POTS interface. The Adtran can also be programmed with up to 10 numbers to accept calls from, and will reject all others. This model does not send Caller-ID information on the analog port.
Adtran has a single page covering
their entire ISU line.