Information Systems:Workabout Pro G2 7527C

Overview

This article is a technical discussion of the Psion WORKABOUT PRO G2 7527C - the RF guns used in the warehouse. This article is intended to be limited to discussing the technical aspects of the device only. Refer to the category RF Guns for additional articles related to the general topic of RF guns.

Topics

Zebra has a very good knowledgebase. Perusing the site, you can find loads of technical resources including reference guides and best practice documents for the Workabout series of devices, as well as Zebra software (e.g. TekTerm).

Hardware specs

 Note: There are 37 RF guns in total, with an additional 1 unit not in use (fitted with a long-range laser which is not really applicable for our use(s)). The 37 guns were purchased in two batches. Where there are spec variations listed below, it is theorized that the 2nd batch came with newer specs, either because Zebra silently upgraded the model with better/different parts, or because of stock availability at the time of purchase. Regardless of the reason, there are considerable differences in specs between the two configurations, and these differences are discussed in the sections below.

• CPU: PXA270 520MHz /PXA270M 624MHz
• RAM: 128MB / 256MB
• Flash:
• Wireless radio: Summit Data 802.11b/g CF (Compact Flash) wireless card.
• Scan engine: Symbol 955 / Symbol 1223HP
• Other notables: High-capacity 4400mAh battery (as opposed to regular battery), with corresponding battery doors (they protrude more).

Scanning module differences

As previously mentioned, there are two different scanning modules (i.e. scan engines) that can be found in our RF guns - the Symbol 955 or the 1223HP. The physical difference (i.e. just by looking at the outer casing) is imperceptible to the untrained eye, but the difference lies in the laser produced by the module - the 955 produces a solid laster, while the 1223HP produces a flickering laser. This correlates to a performance difference - the solid laser samples at a higher rate, so barcode capture is faster. While users may not know the technical aspect of this difference, they invariably prefer guns with the 955 because to them, they work better (and they have a point). Interestingly, TRG noted a difference in durability between the two units.

Andy, TRG
The reason you see 'flickering' is like you say, the 1223 oscillates at a lower rate. This is simply because the size of the mirror won't allow it to oscillate at the same speed as the much smaller mirror in the 955. The 1223 has shown to be more rugged than the 955.

This might actually explain why guns with the 955 are more prone to breakage. Technically, they do get more use, so it may be understandable why we observe a higher rate of repair for those units, but users also report odd and temporary problems that could be related to the inherent durability (or lack thereof), of the 955 (e.g. scanner randomly stops functioning and unit needs to be restarted, or device reboots randomly during use after a scan).

Summit Wireless Radio

The wireless card is 802.11b/g, hence it is only capable of connecting on the 2.4GHz spectrum.

When asked if the wireless card could be upgraded (perhaps to 802.11n or 802.11a (5GHz)), TRG said:

Andy, TRG
The Summit Client is embedded in the OS load. The OS has to be upgraded to a newer revision to upgrade the client. I believe the latest OS load for the WAP2/3 has client version 3.3. There is no a/n radio option for the WAP2 or 3, only the WAP4; it has an a/b/g/n radio built onto the main board.

System storage

These units are not like typical laptops or computers where you can expect all data to persist across shutdowns and reboots. There are three main storage areas that differ in volatility:

• Flash (reserved) -
• Flash (user) - Installed applications
• Registry - stored in RAM, persists across cold and warm resets.

What this means is that depending on the type of bootup/restart, a portion of the previous state is actually wiped and needs to be re-installed. For example, when a device is cold-booted, TekTerm needs to be re-installed.

Persistence mechanisms

Persistence mechanism here really refers to a way to re-establish everything on the device, since there is no getting around applications being wiped when the device is cold-booted. In other words, nothing actually persists.

There are two strategies for persisting settings/state for the RF guns - Total Recall and MobiControl. Total Recall is a built-in mechanism,

Batteries

As per the Zebra knowledgebase, batteries are rated for 1 year or 300 cycles, whichever comes first. We probably want to stretch this out to 1.5-2 years, since the batteries are maintained fairly well (i.e. they're used regularly and charged frequently).