What is Modem Pooling?

Modem Pooling is the centralization of modem resources to a PC or server on a network. By creating a logical pool (or group) of modems on the network, every user can be given dialout access to a modem allowing them to connect to remote modem locations for applications such as banking, medical data transfer, faxing applications, or even as an alternative Internet access for users.

While each user on the network uses a modem application, they are automaticly provided with the next available modem in the pool.

What are the advantages of Modem Pooling?

By pooling modems, you can greatly reduce the number of dedicated modems (and their associated phone line expenses), that your organization requires. An example business with 100 desktop modems that are used an average of 30 minutes per day, could reduce to as few as 8 modems by pooling them.

The NetModem modem pooling software can simplify administration, by creating detailed logs or databases of modem usage, and phone numbers dialed by each user.

NetModem can also increase network security, by restricting DialOut modem access to specific authenticated users, limiting the phone numbers allowed to be dialed, limiting usage hours, and blocking Dial-In access entirly.

In enterprise environments redundant modem servers can be configured, providing a failover solution and improving reliability in case one of the modem servers ever goes down.

What is COM Port Control?

COM Port Control is an extention to the TCP/IP telnet protocol, which allows the client based modem applications to control or monitor line settings on a modem server, such as baud rate, flow control, DCD/DSR and DTR, just as if the modem was connected locally. Not all modem servers support COM port Control, but NetModem Server uses it, and it is also used by the NetDialOut and NetSerial redirector products if it is available on the server. (More Information)

Modem Pooling for DialOut, and RAS for Dial-In

Modem pooling generally refers to DialOut (outbound) usage, but the same pool of modems on a Windows Server can also be assigned to RAS (Remote Access Service is part of the Routing and Remote Access Service) to allow remote users to dial-in to your network. RAS is part of Windows Server. (More Information).

Analog or Digital Modems?

Analog modems are support up to 56K (v.90/v.92) connections, and use POTS (Plain Old Telephone System) phone lines.

Digital Modems support both analog and digital connections. Digital connections are 64k (using a single B channel) or 128k (using two B channels). Digital Modems require digital phone lines, such as:

• ISDN-BRI lines (containing two B channels)
  
• T1 ISDN-PRI lines (containing 24 B channels)
  
• E1 ISDN-PRI lines (Containing 48 B Channels)

Typically larger modem pools (over 16 lines) use digital modems and phone lines, even if they only make analog calls. This is because modem cards and modem servers that support 24, 30, 48, or 60 modems/channels generally require T1 or E1 connections. T1 is primarily used in North America, and E1 is primiarily used in Europe, South America, and the South Pacific.

PC Based Modem Pooling vs a Server-in-a-box

You can build a Windows PC based modem pool using NetModem software with existing modems connected to a multi-port serial card, or using multi-modem PCI cards. The NetModem Server software can also be used as a front-end to enhance an existing non-PC modem pool solution. An advantage to using NetModem Server software is the additional security and logging features. NetModem Server includes unlimited client redirectors.

You can also use a Cisco dedicated Access Server box for your modem pool, using NetDialOut Client redirector software. NetDialOut is designed for Legacy Cisco Access Servers which are no longer in production, such as the AS5200, AS5300, AS5400 series supporting Dual T1 or Dual E1 connections.

If you use a legacy access server which does not support COM Port Control, you can use our NetSerial Client redirector, which works with all brands of non-proprietary modem servers and other remote serial devices.

PC Based Modem Pooling Conclusion

Modem pooling provides significant cost savings for small to enterprise organizations, allowing them to share modems and telephone lines more efficiently, and more securley.

PC Micro specializes in modem pooling solutions. You are welcome to contact us to discuss your needs, or you can request to download a fully functional evaluation of our software.