Knowledgebase

Issue:

With softmodems the modem driver is the most important factor on how well the modem will perform. Softmodems utilize the PC's processor (CPU) to perform digital signal processing. A hardware modem has dedicated hardware that performs these functions and is not affected by the PC's processor usage and interrupts.

Softmodems usually are found built into the motherboard and may be advertised as:

HSP (Host Signal Processor) modem
AC97
LTmodem
PCTel modem
Winmodem
PCI Software modem

Cause:

Since softmodems have been around there have always been reported issues with connections.
Typically we find that a customer with a softmodem that fails to connect properly can attach an external hardware modem and connect successfully.
These modems are dependent on the quality of the software code that drives them and appear to be more sensitive to line noise. Disconnects can also occur if system resources are low as the CPU interrupts may give priority to other tasks.

Solution:

Primary causes of the problems can be corrected by changing one or more of the following on the dial in client workstation modem:

• Ensuring you have the lastest driver for the modem.
• Disabling v.44 compression
• Disabling modem hardware compression.
• Disabling v.92 negotiation (see modem manufacturer for details)
• Disabling v.90 negotiation (see modem manufacturer for details)

Disabling modem hardware compression may be performed on a per connection basis through your dialing application.

The most common compression problem has been seen with software modems negotiating the new v.44 compression (added with the v.92 protocol). Configure the modem to disable negotiation of this protocol.

Most operating systems require that disabling connection protocols be performed globally in the modem hardware configuration.

Note: modification of the Perle's modems can be performed my making changes to it's initialization (refer to User Guide) but it will affect all clients dialing in.