HSP Micromodem 56: A PC-Tel Chipset
By: Bradford W. Liedel
Modems made with the PC-Tel 56k
chipset are some of the cheapest currently on the market. It is an HSP
chipset which stands for Host Signal Processing. In the .pdf file http://www.pctel.com/media/HSP_Whitepap.PDF,
PC-Tel defines the HSP chipset as:
"Put simply, HSP is a software-based technology that employs a portion of the unused
instruction cycles (MIPs) in a host computer's CPU chip's to perform
signal processing and other functions that are normally handled by a separate
Digital Signal Processing (DSP) or controller chip. This has been made practical
by the rapid evolution of the microcomputer."
The lack of a DSP is a severe
blow to the modem's functions. They say that it only uses the unused
instruction cycles, but these modems can actually use 50% or more of the CPU's
processing power when dealing with low end Pentiums. These modems are most
commonly found in E-Machines. Some manufacturers have updated drivers for
these modems, but not many. If the manufacturer of your modem does have
new drivers and/or firmware it is HIGHLY
recommended that you get them.
There is a basic
procedure when trying to get a PC-Tel HSP modem to connect when having
connection troubles or stopping it from getting dropped connections. The
first step is to download the latest drivers for your modem if there are any to
download. The second step is as follows:
Lower the port speed to 57,600,
then lower the Fifo buffers by one setting on both transmit and recieve.
Then enter the initialization string: AT&F&C1&D2&K3W1
If the modem is having further
issues try dropping the Fifo buffers to the lowest setting and changing the
string to: AT&F&C1&D2&K3%N5W1
If these issues STILL persist
change the init string to: AT&FS37=12N1
sets the modem to v.34
mode and the N1 forces
the modem to use the s-register number 37. The final two inits that you
can try are AT&FS37=12N1%N5 or
dealing with the s-register s91=#. This register can actually compensate
for your phone line's voltage level! I would try s91=5
and then s91=15
and perhaps play around with it a bit. The default value is s91=10.
are also several tricky things to try to get the modem to work. If the
computer has a S3 Video Card then try lowering the graphics resolution.
Also, if you are dialing into a cisco server, Cisco remote access has 2
available modems - Microcom and Mica. Recent Microcom firmware should be ok with
the PCTel chipset, however Cisco MICA modems didn't support V.90 with PCTel
until portware 184.108.40.206 which was released at the end of March 99. If a user is dialing
into this type of site the portware needs to be upgraded or v34 must be
used. Cyrix processors will have a harder time with these modems than
Intel processors. There is a Cyrix firmware upgrade for the PC-Tel modems,
but if you can't find updated drivers you probably won't be able to find this
one. There are no AMD drivers for the PC-Tel HSP's that I know of, the
Intel drivers should hopefully work with these chips.
and tricks to try: Try adding commas(2-4) after the phone number.
Try ATZ. Try changing W1 to W2. Try %N4 instead of %N5 or %N6.
Try adding %E1 or %E3. It is also possible that %E0 will help and changing
flow control from RTS/CTS(hardware) to
XON/XOFF(software) may actually help as
well. In fact, that makes sense in a way since it is a software
Here is a partial list of
manufacturer websites who make modems with the PC-Tel HSP chipset:
BTC(Behavior Tech Computer):
Lectron Co. Ltd.:
This page was last modified on Saturday, 05-Feb-2011 15:10:48 EST.